Annual report pursuant to Section 13 and 15(d)

Schedule III (Details)

v2.4.0.6
Schedule III (Details) (USD $)
12 Months Ended
Dec. 31, 2012
units
sqft
Dec. 31, 2011
sqft
Dec. 31, 2010
sqft
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land $ 528,576,000 [1]    
Initial Cost, Buildings and Improvements 1,483,293,000 [1]    
Net Improvements (Retirement) since Acquisition 517,264,000    
Gross Amounts at Which Carried at December 31, 2011, Land 529,291,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 1,999,840,000    
Gross Amounts at Which Carried at December 31, 2011, Total 2,529,131,000 [2]    
Accumulated Depreciation at December 31, 2011 610,536,000    
Net Rentable Square Feet 10,725,000 [3]    
Units 2,540    
Secured Debt 342,970,000 423,291,000  
Mortgage notes payable 342,970,000 427,710,000  
Real estate, federal income tax basis 2,148,544,000    
Area of land 213,000 3,272,000 638,000
Land Available for Development 7,500,000    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, beginning of period 2,449,872,000 2,443,127,000 2,341,461,000
Property acquisitions 47,772,000 [4] 352,658,000 [4] 140,584,000 [4]
Improvements 59,664,000 [4] 36,386,000 [4] 28,196,000 [4]
Impairment write-down (2,097,000) (16,416,000) 0
Write-off of disposed assets (1,450,000) (1,648,000) (866,000)
Property sales (24,630,000) (364,235,000) (66,248,000)
Balance, end of period 2,529,131,000 2,449,872,000 2,443,127,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, beginning of period 535,732,000 538,786,000 475,245,000
Depreciation 84,949,000 84,167,000 83,302,000
Impairment write-down 0 (1,291,000) 0
Write-off of disposed assets (1,124,000) (1,648,000) (866,000)
Property sales (9,021,000) (84,282,000) (18,895,000)
Balance, end of period 610,536,000 535,732,000 538,786,000
Multifamily Properties [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 70,956,000 [1]    
Initial Cost, Buildings and Improvements 85,559,000 [1]    
Net Improvements (Retirement) since Acquisition 211,147,000    
Gross Amounts at Which Carried at December 31, 2011, Land 81,918,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 285,743,000    
Gross Amounts at Which Carried at December 31, 2011, Total 367,661,000 [2]    
Accumulated Depreciation at December 31, 2011 120,036,000    
Net Rentable Square Feet 2,137,000 [3]    
3801 Connecticut [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 420,000 [1],[5]    
Initial Cost, Buildings and Improvements 2,678,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 9,023,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 420,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,702,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 12,122,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 8,504,000 [5]    
Year of Construction Jan. 01, 1951 [5]    
Date of Acquisition Jan. 01, 1963 [5]    
Net Rentable Square Feet 179,000 [3],[5]    
Units 308 [5]    
Depreciation Life 30 years [5],[6]    
Roosevelt Towers [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 336,000 [1]    
Initial Cost, Buildings and Improvements 1,996,000 [1]    
Net Improvements (Retirement) since Acquisition 9,881,000    
Gross Amounts at Which Carried at December 31, 2011, Land 336,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,877,000    
Gross Amounts at Which Carried at December 31, 2011, Total 12,213,000 [2]    
Accumulated Depreciation at December 31, 2011 7,180,000    
Year of Construction Jan. 01, 1964    
Date of Acquisition May 01, 1965    
Net Rentable Square Feet 170,000 [3]    
Units 191    
Depreciation Life 40 years [6]    
Country Club Towers [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 299,000 [1]    
Initial Cost, Buildings and Improvements 2,562,000 [1]    
Net Improvements (Retirement) since Acquisition 14,461,000    
Gross Amounts at Which Carried at December 31, 2011, Land 299,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 17,023,000    
Gross Amounts at Which Carried at December 31, 2011, Total 17,322,000 [2]    
Accumulated Depreciation at December 31, 2011 9,472,000    
Year of Construction Jan. 01, 1965    
Date of Acquisition Jul. 01, 1969    
Net Rentable Square Feet 159,000 [3]    
Units 227    
Depreciation Life 35 years [6]    
Park Adams [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 287,000 [1]    
Initial Cost, Buildings and Improvements 1,654,000 [1]    
Net Improvements (Retirement) since Acquisition 9,141,000    
Gross Amounts at Which Carried at December 31, 2011, Land 287,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 10,795,000    
Gross Amounts at Which Carried at December 31, 2011, Total 11,082,000 [2]    
Accumulated Depreciation at December 31, 2011 7,386,000    
Year of Construction Jan. 01, 1959    
Date of Acquisition Jan. 01, 1969    
Net Rentable Square Feet 173,000 [3]    
Units 200    
Depreciation Life 35 years [6]    
Munson Hill Towers [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 322,000 [1]    
Initial Cost, Buildings and Improvements 3,337,000 [1]    
Net Improvements (Retirement) since Acquisition 14,847,000    
Gross Amounts at Which Carried at December 31, 2011, Land 322,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 18,183,000    
Gross Amounts at Which Carried at December 31, 2011, Total 18,505,000 [2]    
Accumulated Depreciation at December 31, 2011 12,589,000    
Year of Construction Jan. 01, 1963    
Date of Acquisition Jan. 01, 1970    
Net Rentable Square Feet 258,000 [3]    
Units 279    
Depreciation Life 33 years [6]    
The Ashby at McLean [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,356,000 [1]    
Initial Cost, Buildings and Improvements 17,102,000 [1]    
Net Improvements (Retirement) since Acquisition 15,148,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,356,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 32,250,000    
Gross Amounts at Which Carried at December 31, 2011, Total 36,606,000 [2]    
Accumulated Depreciation at December 31, 2011 17,975,000    
Year of Construction Jan. 01, 1982    
Date of Acquisition Aug. 01, 1996    
Net Rentable Square Feet 274,000 [3]    
Units 256    
Depreciation Life 30 years [6]    
Walker House Apartments [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 2,851,000 [1],[5]    
Initial Cost, Buildings and Improvements 7,946,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 6,688,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 2,851,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 14,634,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 17,485,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 8,508,000 [5]    
Year of Construction Jan. 01, 1971 [5]    
Date of Acquisition Mar. 01, 1996 [5]    
Net Rentable Square Feet 157,000 [3],[5]    
Units 212 [5]    
Depreciation Life 30 years [5],[6]    
Bethesda Hill Apartments [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 3,900,000 [1],[5]    
Initial Cost, Buildings and Improvements 13,412,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 11,903,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 3,900,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,315,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 29,215,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 13,593,000 [5]    
Year of Construction Jan. 01, 1986 [5]    
Date of Acquisition Nov. 01, 1997 [5]    
Net Rentable Square Feet 225,000 [3],[5]    
Units 195 [5]    
Depreciation Life 30 years [5],[6]    
Bennett Park [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,861,000 [1]    
Initial Cost, Buildings and Improvements 917,000 [1]    
Net Improvements (Retirement) since Acquisition 78,855,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,774,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 77,859,000    
Gross Amounts at Which Carried at December 31, 2011, Total 82,633,000 [2]    
Accumulated Depreciation at December 31, 2011 20,017,000    
Year of Construction Jan. 01, 2007    
Date of Acquisition Feb. 01, 2001    
Net Rentable Square Feet 214,000 [3]    
Units 224    
Depreciation Life 28 years [6]    
The Clayborne [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 269,000 [1]    
Initial Cost, Buildings and Improvements 0 [1]    
Net Improvements (Retirement) since Acquisition 30,451,000    
Gross Amounts at Which Carried at December 31, 2011, Land 699,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 30,020,000    
Gross Amounts at Which Carried at December 31, 2011, Total 30,719,000 [2]    
Accumulated Depreciation at December 31, 2011 8,994,000    
Year of Construction Jan. 01, 2008    
Date of Acquisition Jun. 01, 2003    
Net Rentable Square Feet 60,000 [3]    
Units 74    
Depreciation Life 26 years [6]    
The Kenmore [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 28,222,000 [1],[5]    
Initial Cost, Buildings and Improvements 33,955,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 2,130,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 28,222,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 36,085,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 64,307,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 5,818,000 [5]    
Year of Construction Jan. 01, 1948 [5]    
Date of Acquisition Sep. 01, 2008 [5]    
Net Rentable Square Feet 268,000 [3],[5]    
Units 374 [5]    
Depreciation Life 30 years [5],[6]    
North Glebe, 650 and 1219 First Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Land Available for Development 35,500,000    
Six Fifty North Glebe Road [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [7]    
Initial Cost, Land 12,787,000 [1],[7]    
Initial Cost, Buildings and Improvements 0 [1],[7]    
Net Improvements (Retirement) since Acquisition 2,858,000 [7]    
Gross Amounts at Which Carried at December 31, 2011, Land 15,645,000 [7]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 0 [7]    
Gross Amounts at Which Carried at December 31, 2011, Total 15,645,000 [2],[7]    
Accumulated Depreciation at December 31, 2011 0 [7]    
Date of Acquisition Jun. 01, 2011 [7]    
Net Rentable Square Feet 0 [3],[7]    
Units 0 [7]    
1219 First Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [7]    
Initial Cost, Land 14,046,000 [1],[7]    
Initial Cost, Buildings and Improvements 0 [1],[7]    
Net Improvements (Retirement) since Acquisition 5,761,000 [7]    
Gross Amounts at Which Carried at December 31, 2011, Land 19,807,000 [7]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 0 [7]    
Gross Amounts at Which Carried at December 31, 2011, Total 19,807,000 [2],[7]    
Accumulated Depreciation at December 31, 2011 0 [7]    
Date of Acquisition Nov. 01, 2011 [7]    
Net Rentable Square Feet 0 [3],[7]    
Units 0 [5],[7]    
Office Buildings [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 274,683,000 [1]    
Initial Cost, Buildings and Improvements 863,221,000 [1]    
Net Improvements (Retirement) since Acquisition 204,157,000    
Gross Amounts at Which Carried at December 31, 2011, Land 263,812,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 1,078,249,000    
Gross Amounts at Which Carried at December 31, 2011, Total 1,342,061,000 [2]    
Accumulated Depreciation at December 31, 2011 309,483,000    
Net Rentable Square Feet 4,855,000 [3]    
1901 Pennsylvania Avenue [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 892,000 [1]    
Initial Cost, Buildings and Improvements 3,481,000 [1]    
Net Improvements (Retirement) since Acquisition 15,100,000    
Gross Amounts at Which Carried at December 31, 2011, Land 892,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 18,581,000    
Gross Amounts at Which Carried at December 31, 2011, Total 19,473,000 [2]    
Accumulated Depreciation at December 31, 2011 13,478,000    
Year of Construction Jan. 01, 1960    
Date of Acquisition May 01, 1977    
Net Rentable Square Feet 99,000    
Depreciation Life 28 years [6]    
51 Monroe Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 840,000 [1]    
Initial Cost, Buildings and Improvements 10,869,000 [1]    
Net Improvements (Retirement) since Acquisition 24,173,000    
Gross Amounts at Which Carried at December 31, 2011, Land 840,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 35,042,000    
Gross Amounts at Which Carried at December 31, 2011, Total 35,882,000 [2]    
Accumulated Depreciation at December 31, 2011 24,898,000    
Year of Construction Jan. 01, 1975    
Date of Acquisition Aug. 01, 1979    
Net Rentable Square Feet 221,000    
Depreciation Life 41 years [6]    
515 King Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,102,000 [1]    
Initial Cost, Buildings and Improvements 3,931,000 [1]    
Net Improvements (Retirement) since Acquisition 5,125,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,102,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 9,056,000    
Gross Amounts at Which Carried at December 31, 2011, Total 13,158,000 [2]    
Accumulated Depreciation at December 31, 2011 4,662,000    
Year of Construction Jan. 01, 1966    
Date of Acquisition Jul. 01, 1992    
Net Rentable Square Feet 74,000    
Depreciation Life 50 years [6]    
6110 Executive Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 4,621,000 [1]    
Initial Cost, Buildings and Improvements 11,926,000 [1]    
Net Improvements (Retirement) since Acquisition 11,947,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,621,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 23,873,000    
Gross Amounts at Which Carried at December 31, 2011, Total 28,494,000 [2]    
Accumulated Depreciation at December 31, 2011 15,372,000    
Year of Construction Jan. 01, 1971    
Date of Acquisition Jan. 01, 1995    
Net Rentable Square Feet 202,000    
Depreciation Life 30 years [6]    
1220 19th Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 7,803,000 [1]    
Initial Cost, Buildings and Improvements 11,366,000 [1]    
Net Improvements (Retirement) since Acquisition 9,690,000    
Gross Amounts at Which Carried at December 31, 2011, Land 7,802,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 21,057,000    
Gross Amounts at Which Carried at December 31, 2011, Total 28,859,000 [2]    
Accumulated Depreciation at December 31, 2011 10,065,000    
Year of Construction Jan. 01, 1976    
Date of Acquisition Nov. 01, 1995    
Net Rentable Square Feet 103,000    
Depreciation Life 30 years [6]    
1600 Wilson Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 6,661,000 [1]    
Initial Cost, Buildings and Improvements 16,742,000 [1]    
Net Improvements (Retirement) since Acquisition 14,806,000    
Gross Amounts at Which Carried at December 31, 2011, Land 6,661,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 31,548,000    
Gross Amounts at Which Carried at December 31, 2011, Total 38,209,000 [2]    
Accumulated Depreciation at December 31, 2011 15,163,000    
Year of Construction Jan. 01, 1973    
Date of Acquisition Oct. 01, 1997    
Net Rentable Square Feet 167,000    
Depreciation Life 30 years [6]    
7900 Westpark Drive [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 12,049,000 [1]    
Initial Cost, Buildings and Improvements 71,825,000 [1]    
Net Improvements (Retirement) since Acquisition 36,150,000    
Gross Amounts at Which Carried at December 31, 2011, Land 12,049,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 107,975,000    
Gross Amounts at Which Carried at December 31, 2011, Total 120,024,000 [2]    
Accumulated Depreciation at December 31, 2011 56,264,000    
Year of Construction Jan. 01, 1972    
Date of Acquisition Nov. 01, 1997    
Net Rentable Square Feet 538,000    
Depreciation Life 30 years [6]    
600 Jefferson Plaza [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 2,296,000 [1]    
Initial Cost, Buildings and Improvements 12,188,000 [1]    
Net Improvements (Retirement) since Acquisition 5,512,000    
Gross Amounts at Which Carried at December 31, 2011, Land 2,296,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 17,700,000    
Gross Amounts at Which Carried at December 31, 2011, Total 19,996,000 [2]    
Accumulated Depreciation at December 31, 2011 8,346,000    
Year of Construction Jan. 01, 1985    
Date of Acquisition May 01, 1999    
Net Rentable Square Feet 113,000    
Depreciation Life 30 years [6]    
Wayne Plaza [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 1,564,000 [1]    
Initial Cost, Buildings and Improvements 6,243,000 [1]    
Net Improvements (Retirement) since Acquisition 7,928,000    
Gross Amounts at Which Carried at December 31, 2011, Land 1,564,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 14,171,000    
Gross Amounts at Which Carried at December 31, 2011, Total 15,735,000 [2]    
Accumulated Depreciation at December 31, 2011 6,537,000    
Year of Construction Jan. 01, 1970    
Date of Acquisition May 01, 2000    
Net Rentable Square Feet 96,000    
Depreciation Life 30 years [6]    
Courthouse Square [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 0 [1]    
Initial Cost, Buildings and Improvements 17,096,000 [1]    
Net Improvements (Retirement) since Acquisition 6,677,000    
Gross Amounts at Which Carried at December 31, 2011, Land 0    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 23,773,000    
Gross Amounts at Which Carried at December 31, 2011, Total 23,773,000 [2]    
Accumulated Depreciation at December 31, 2011 9,844,000    
Year of Construction Jan. 01, 1979    
Date of Acquisition Oct. 01, 2000    
Net Rentable Square Feet 115,000    
Depreciation Life 30 years [6]    
One Central Plaza [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 5,480,000 [1]    
Initial Cost, Buildings and Improvements 39,107,000 [1]    
Net Improvements (Retirement) since Acquisition 16,745,000    
Gross Amounts at Which Carried at December 31, 2011, Land 5,480,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 55,852,000    
Gross Amounts at Which Carried at December 31, 2011, Total 61,332,000 [2]    
Accumulated Depreciation at December 31, 2011 23,755,000    
Year of Construction Jan. 01, 1974    
Date of Acquisition Apr. 01, 2001    
Net Rentable Square Feet 267,000    
Depreciation Life 30 years [6]    
Atrium Building [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 3,182,000 [1]    
Initial Cost, Buildings and Improvements 11,281,000 [1]    
Net Improvements (Retirement) since Acquisition 2,987,000    
Gross Amounts at Which Carried at December 31, 2011, Land 3,182,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 14,268,000    
Gross Amounts at Which Carried at December 31, 2011, Total 17,450,000 [2]    
Accumulated Depreciation at December 31, 2011 5,922,000    
Year of Construction Jan. 01, 1980    
Date of Acquisition Jul. 01, 2002    
Net Rentable Square Feet 79,000    
Depreciation Life 30 years [6]    
Area of land 79,000    
1776 G Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 31,500,000 [1]    
Initial Cost, Buildings and Improvements 54,327,000 [1]    
Net Improvements (Retirement) since Acquisition 4,383,000    
Gross Amounts at Which Carried at December 31, 2011, Land 31,500,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 58,710,000    
Gross Amounts at Which Carried at December 31, 2011, Total 90,210,000 [2]    
Accumulated Depreciation at December 31, 2011 20,958,000    
Year of Construction Jan. 01, 1979    
Date of Acquisition Aug. 01, 2003    
Net Rentable Square Feet 263,000    
Depreciation Life 30 years [6]    
Dulles Station II [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [8]    
Initial Cost, Land 15,001,000 [1],[8]    
Initial Cost, Buildings and Improvements 494,000 [1],[8]    
Net Improvements (Retirement) since Acquisition (3,425,000) [8]    
Gross Amounts at Which Carried at December 31, 2011, Land 4,130,000 [8]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 7,940,000 [8]    
Gross Amounts at Which Carried at December 31, 2011, Total 12,070,000 [2],[8]    
Accumulated Depreciation at December 31, 2011 179,000 [8]    
Date of Acquisition Dec. 01, 2005 [8]    
Net Rentable Square Feet 0 [8]    
Land Placed In Service 500,000    
6565 Arlington Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 5,584,000 [1],[5]    
Initial Cost, Buildings and Improvements 23,195,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 4,677,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 5,584,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 27,872,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 33,456,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 7,719,000 [5]    
Year of Construction Jan. 01, 1967 [5]    
Date of Acquisition Aug. 01, 2006 [5]    
Net Rentable Square Feet 132,000    
Depreciation Life 30 years [5],[6]    
West Gude Drive [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 11,580,000 [1],[5]    
Initial Cost, Buildings and Improvements 43,240,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 8,208,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 11,580,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 51,448,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 63,028,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 12,807,000 [5]    
Year of Construction Jan. 01, 1984 [5]    
Date of Acquisition Aug. 01, 2006 [5]    
Net Rentable Square Feet 275,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
Monument II [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 10,244,000 [1]    
Initial Cost, Buildings and Improvements 65,205,000 [1]    
Net Improvements (Retirement) since Acquisition 3,737,000    
Gross Amounts at Which Carried at December 31, 2011, Land 10,244,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 68,942,000    
Gross Amounts at Which Carried at December 31, 2011, Total 79,186,000 [2]    
Accumulated Depreciation at December 31, 2011 15,247,000    
Year of Construction Jan. 01, 2000    
Date of Acquisition Mar. 01, 2007    
Net Rentable Square Feet 207,000    
Depreciation Life 30 years [6]    
Woodholme Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 2,194,000 [1]    
Initial Cost, Buildings and Improvements 16,711,000 [1]    
Net Improvements (Retirement) since Acquisition 1,794,000    
Gross Amounts at Which Carried at December 31, 2011, Land 2,194,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 18,505,000    
Gross Amounts at Which Carried at December 31, 2011, Total 20,699,000 [2]    
Accumulated Depreciation at December 31, 2011 4,039,000    
Year of Construction Jan. 01, 1989    
Date of Acquisition Jun. 01, 2007    
Net Rentable Square Feet 80,000    
Depreciation Life 30 years [6]    
2000 M Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 0 [1]    
Initial Cost, Buildings and Improvements 61,101,000 [1]    
Net Improvements (Retirement) since Acquisition 16,427,000    
Gross Amounts at Which Carried at December 31, 2011, Land 0    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 77,528,000    
Gross Amounts at Which Carried at December 31, 2011, Total 77,528,000 [2]    
Accumulated Depreciation at December 31, 2011 13,671,000    
Year of Construction Jan. 01, 1971    
Date of Acquisition Dec. 01, 2007    
Net Rentable Square Feet 228,000    
Depreciation Life 30 years [6]    
M Street 2445 [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 46,887,000 [1],[5]    
Initial Cost, Buildings and Improvements 106,743,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 2,634,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 46,887,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 109,377,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 156,264,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 17,462,000 [5]    
Year of Construction Jan. 01, 1986 [5]    
Date of Acquisition Dec. 01, 2008 [5]    
Net Rentable Square Feet 290,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
Quantico Building E [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,518,000 [1]    
Initial Cost, Buildings and Improvements 24,801,000 [1]    
Net Improvements (Retirement) since Acquisition 165,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,518,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 24,966,000    
Gross Amounts at Which Carried at December 31, 2011, Total 29,484,000 [2]    
Accumulated Depreciation at December 31, 2011 3,692,000    
Year of Construction Jan. 01, 2007    
Date of Acquisition Jun. 01, 2010    
Net Rentable Square Feet 134,000    
Depreciation Life 30 years [6]    
Quantico Building G [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,897,000 [1]    
Initial Cost, Buildings and Improvements 25,376,000 [1]    
Net Improvements (Retirement) since Acquisition 126,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,898,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,501,000    
Gross Amounts at Which Carried at December 31, 2011, Total 30,399,000 [2]    
Accumulated Depreciation at December 31, 2011 3,921,000    
Year of Construction Jan. 01, 2009    
Date of Acquisition Jun. 01, 2010    
Net Rentable Square Feet 136,000    
Depreciation Life 30 years [6]    
1140 Connecticut Avenue [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 25,226,000 [1]    
Initial Cost, Buildings and Improvements 50,495,000 [1]    
Net Improvements (Retirement) since Acquisition 5,306,000    
Gross Amounts at Which Carried at December 31, 2011, Land 25,226,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 55,801,000    
Gross Amounts at Which Carried at December 31, 2011, Total 81,027,000 [2]    
Accumulated Depreciation at December 31, 2011 4,712,000    
Year of Construction Jan. 01, 1966    
Date of Acquisition Jan. 01, 2011    
Net Rentable Square Feet 188,000    
Depreciation Life 30 years [6]    
1227 25th Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 17,505,000 [1]    
Initial Cost, Buildings and Improvements 21,319,000 [1]    
Net Improvements (Retirement) since Acquisition 668,000    
Gross Amounts at Which Carried at December 31, 2011, Land 17,505,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 21,987,000    
Gross Amounts at Which Carried at December 31, 2011, Total 39,492,000 [2]    
Accumulated Depreciation at December 31, 2011 2,010,000    
Year of Construction Jan. 01, 1988    
Date of Acquisition Mar. 01, 2011    
Net Rentable Square Feet 132,000    
Depreciation Life 30 years [6]    
Braddock Place Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 18,817,000 [1],[5]    
Initial Cost, Buildings and Improvements 71,250,000 [1]    
Net Improvements (Retirement) since Acquisition 2,238,000    
Gross Amounts at Which Carried at December 31, 2011, Land 18,817,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 73,488,000    
Gross Amounts at Which Carried at December 31, 2011, Total 92,305,000 [2]    
Accumulated Depreciation at December 31, 2011 5,009,000    
Year of Construction Jan. 01, 1985    
Date of Acquisition Sep. 01, 2011    
Net Rentable Square Feet 351,000    
Depreciation Life 30 years [6]    
John Marshall II Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 13,490,000 [1],[5]    
Initial Cost, Buildings and Improvements 53,024,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 95,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 13,490,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 53,119,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 66,609,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 2,856,000 [5]    
Year of Construction Jan. 01, 1996 [5]    
Date of Acquisition Sep. 01, 2011 [5]    
Net Rentable Square Feet 223,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
Fairgate at Ballston [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 17,750,000 [1]    
Initial Cost, Buildings and Improvements 29,885,000 [1]    
Net Improvements (Retirement) since Acquisition 284,000    
Gross Amounts at Which Carried at December 31, 2011, Land 17,750,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 30,169,000    
Gross Amounts at Which Carried at December 31, 2011, Total 47,919,000 [2]    
Accumulated Depreciation at December 31, 2011 895,000    
Year of Construction Jan. 01, 1988    
Date of Acquisition Jun. 01, 2012    
Net Rentable Square Feet 142,000    
Depreciation Life 30 years [6]    
Medical Office [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 61,179,000 [1]    
Initial Cost, Buildings and Improvements 308,148,000 [1]    
Net Improvements (Retirement) since Acquisition 37,546,000    
Gross Amounts at Which Carried at December 31, 2011, Land 61,225,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 345,647,000    
Gross Amounts at Which Carried at December 31, 2011, Total 406,872,000 [2]    
Accumulated Depreciation at December 31, 2011 95,797,000    
Net Rentable Square Feet 1,285,000 [3]    
Woodburn Medical Park I [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,563,000 [1]    
Initial Cost, Buildings and Improvements 12,460,000 [1]    
Net Improvements (Retirement) since Acquisition 4,328,000    
Gross Amounts at Which Carried at December 31, 2011, Land 2,563,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 16,788,000    
Gross Amounts at Which Carried at December 31, 2011, Total 19,351,000 [2]    
Accumulated Depreciation at December 31, 2011 8,105,000    
Year of Construction Jan. 01, 1984    
Date of Acquisition Nov. 01, 1998    
Net Rentable Square Feet 73,000    
Depreciation Life 30 years [6]    
Woodburn Medical Park II [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,632,000 [1]    
Initial Cost, Buildings and Improvements 17,574,000 [1]    
Net Improvements (Retirement) since Acquisition 4,310,000    
Gross Amounts at Which Carried at December 31, 2011, Land 2,632,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 21,884,000    
Gross Amounts at Which Carried at December 31, 2011, Total 24,516,000 [2]    
Accumulated Depreciation at December 31, 2011 10,261,000    
Year of Construction Jan. 01, 1988    
Date of Acquisition Nov. 01, 1998    
Net Rentable Square Feet 96,000    
Depreciation Life 30 years [6]    
8501 Arlington Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 2,071,000 [1],[5]    
Initial Cost, Buildings and Improvements 26,317,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 1,281,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 2,071,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 27,597,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 29,668,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 9,061,000 [5]    
Year of Construction Jan. 01, 2000 [5]    
Date of Acquisition Oct. 01, 2003 [5]    
Net Rentable Square Feet 92,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
8503 Arlington Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 1,598,000 [1],[5]    
Initial Cost, Buildings and Improvements 25,850,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 1,478,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 1,598,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 27,328,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 28,926,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 8,754,000 [5]    
Year of Construction Jan. 01, 2001 [5]    
Date of Acquisition Oct. 01, 2003 [5]    
Net Rentable Square Feet 88,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
8505 Arlington Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 2,819,000 [1],[5]    
Initial Cost, Buildings and Improvements 19,680,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 692,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 2,819,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 20,372,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 23,191,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 6,825,000 [5]    
Year of Construction Jan. 01, 2002 [5]    
Date of Acquisition Oct. 01, 2003 [5]    
Net Rentable Square Feet 75,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
Shady Grove Medical Village Ii Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 1,995,000 [1]    
Initial Cost, Buildings and Improvements 16,601,000 [1]    
Net Improvements (Retirement) since Acquisition 1,524,000    
Gross Amounts at Which Carried at December 31, 2011, Land 1,995,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 18,125,000    
Gross Amounts at Which Carried at December 31, 2011, Total 20,120,000 [2]    
Accumulated Depreciation at December 31, 2011 5,129,000    
Year of Construction Jan. 01, 1999    
Date of Acquisition Aug. 01, 2004    
Net Rentable Square Feet 66,000    
Depreciation Life 30 years [6]    
8301 Arlington Boulevard [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 1,251,000 [1]    
Initial Cost, Buildings and Improvements 6,589,000 [1]    
Net Improvements (Retirement) since Acquisition 1,766,000    
Gross Amounts at Which Carried at December 31, 2011, Land 1,251,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 8,355,000    
Gross Amounts at Which Carried at December 31, 2011, Total 9,606,000 [2]    
Accumulated Depreciation at December 31, 2011 2,598,000    
Year of Construction Jan. 01, 1965    
Date of Acquisition Oct. 01, 2004    
Net Rentable Square Feet 50,000    
Depreciation Life 30 years [6]    
Alexandria Professional Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 6,783,000 [1]    
Initial Cost, Buildings and Improvements 19,676,000 [1]    
Net Improvements (Retirement) since Acquisition 5,955,000    
Gross Amounts at Which Carried at December 31, 2011, Land 6,783,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,631,000    
Gross Amounts at Which Carried at December 31, 2011, Total 32,414,000 [2]    
Accumulated Depreciation at December 31, 2011 6,019,000    
Year of Construction Jan. 01, 1968    
Date of Acquisition Apr. 01, 2006    
Net Rentable Square Feet 117,000    
Depreciation Life 30 years [6]    
Medical Center Drive 9707 [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 3,069,000 [1],[5]    
Initial Cost, Buildings and Improvements 11,777,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 1,151,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 3,069,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 12,928,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 15,997,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 3,246,000 [5]    
Year of Construction Jan. 01, 1994 [5]    
Date of Acquisition Apr. 01, 2006 [5]    
Net Rentable Square Feet 38,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
15001 Shady Grove Road [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 4,094,000 [1]    
Initial Cost, Buildings and Improvements 16,410,000 [1]    
Net Improvements (Retirement) since Acquisition 1,688,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,094,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 18,098,000    
Gross Amounts at Which Carried at December 31, 2011, Total 22,192,000 [2]    
Accumulated Depreciation at December 31, 2011 4,694,000    
Year of Construction Jan. 01, 1999    
Date of Acquisition Apr. 01, 2006    
Net Rentable Square Feet 51,000    
Depreciation Life 30 years [6]    
Shady Grove Road 15005 [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 4,186,000 [1],[5]    
Initial Cost, Buildings and Improvements 17,548,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 691,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 4,186,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 18,239,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 22,425,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 4,227,000 [5]    
Year of Construction Jan. 01, 2002 [5]    
Date of Acquisition Jul. 01, 2006 [5]    
Net Rentable Square Feet 51,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
2440 M Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 12,500,000 [1]    
Initial Cost, Buildings and Improvements 37,321,000 [1]    
Net Improvements (Retirement) since Acquisition 5,099,000    
Gross Amounts at Which Carried at December 31, 2011, Land 12,500,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 42,420,000    
Gross Amounts at Which Carried at December 31, 2011, Total 54,920,000 [2]    
Accumulated Depreciation at December 31, 2011 9,787,000    
Year of Construction Jan. 01, 1986    
Date of Acquisition Mar. 01, 2007    
Net Rentable Square Feet 113,000    
Depreciation Life 30 years [6]    
Woodholme Medical Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 3,744,000 [1],[5]    
Initial Cost, Buildings and Improvements 24,587,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 2,015,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 3,744,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 26,602,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 30,346,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 5,881,000 [5]    
Year of Construction Jan. 01, 1996 [5]    
Date of Acquisition Jun. 01, 2007 [5]    
Net Rentable Square Feet 127,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
Ashburn Farm Professional Cntr [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 3,770,000 [1],[5]    
Initial Cost, Buildings and Improvements 19,200,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 1,458,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 3,770,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 20,658,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 24,428,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 4,412,000 [5]    
Year of Construction Jan. 01, 1998 [5]    
Date of Acquisition Jun. 01, 2007 [5]    
Net Rentable Square Feet 75,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
CentreMed I & II [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,062,000 [1]    
Initial Cost, Buildings and Improvements 12,506,000 [1]    
Net Improvements (Retirement) since Acquisition 759,000    
Gross Amounts at Which Carried at December 31, 2011, Land 2,062,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 13,265,000    
Gross Amounts at Which Carried at December 31, 2011, Total 15,327,000 [2]    
Accumulated Depreciation at December 31, 2011 2,703,000    
Year of Construction Jan. 01, 1998    
Date of Acquisition Aug. 01, 2007    
Net Rentable Square Feet 52,000    
Depreciation Life 30 years [6]    
4661 Kenmore Avenue [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [8]    
Initial Cost, Land 3,764,000 [1],[8]    
Initial Cost, Buildings and Improvements 0 [1],[8]    
Net Improvements (Retirement) since Acquisition 46,000 [8]    
Gross Amounts at Which Carried at December 31, 2011, Land 3,810,000 [8]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 0 [8]    
Gross Amounts at Which Carried at December 31, 2011, Total 3,810,000 [2],[8]    
Accumulated Depreciation at December 31, 2011 0 [8]    
Date of Acquisition Aug. 01, 2007 [8]    
Area of land 0.8    
Sterling Medical Office Bldg [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 970,000 [1]    
Initial Cost, Buildings and Improvements 5,274,000 [1]    
Net Improvements (Retirement) since Acquisition 895,000    
Gross Amounts at Which Carried at December 31, 2011, Land 970,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 6,169,000    
Gross Amounts at Which Carried at December 31, 2011, Total 7,139,000 [2]    
Accumulated Depreciation at December 31, 2011 1,434,000    
Year of Construction Jan. 01, 1986    
Date of Acquisition May 01, 2008    
Net Rentable Square Feet 36,000    
Depreciation Life 30 years [6]    
Lansdowne Medical Office Building [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 1,308,000 [1]    
Initial Cost, Buildings and Improvements 18,778,000 [1]    
Net Improvements (Retirement) since Acquisition 2,410,000    
Gross Amounts at Which Carried at December 31, 2011, Land 1,308,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 21,188,000    
Gross Amounts at Which Carried at December 31, 2011, Total 22,496,000 [2]    
Accumulated Depreciation at December 31, 2011 2,661,000    
Year of Construction Jan. 01, 2009    
Date of Acquisition Aug. 01, 2009    
Net Rentable Square Feet 85,000    
Depreciation Life 30 years [6]    
Retail Centers [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 121,758,000 [1]    
Initial Cost, Buildings and Improvements 226,365,000 [1]    
Net Improvements (Retirement) since Acquisition 64,414,000    
Gross Amounts at Which Carried at December 31, 2011, Land 122,336,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 290,201,000    
Gross Amounts at Which Carried at December 31, 2011, Total 412,537,000 [2]    
Accumulated Depreciation at December 31, 2011 85,220,000    
Net Rentable Square Feet 2,448,000 [3]    
Takoma Park [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 415,000 [1]    
Initial Cost, Buildings and Improvements 1,084,000 [1]    
Net Improvements (Retirement) since Acquisition 155,000    
Gross Amounts at Which Carried at December 31, 2011, Land 415,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 1,239,000    
Gross Amounts at Which Carried at December 31, 2011, Total 1,654,000 [2]    
Accumulated Depreciation at December 31, 2011 1,170,000    
Year of Construction Jan. 01, 1962    
Date of Acquisition Jul. 01, 1963    
Net Rentable Square Feet 51,000    
Depreciation Life 50 years [6]    
Westminster [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 519,000 [1]    
Initial Cost, Buildings and Improvements 1,775,000 [1]    
Net Improvements (Retirement) since Acquisition 9,140,000    
Gross Amounts at Which Carried at December 31, 2011, Land 519,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 10,915,000    
Gross Amounts at Which Carried at December 31, 2011, Total 11,434,000 [2]    
Accumulated Depreciation at December 31, 2011 6,183,000    
Year of Construction Jan. 01, 1969    
Date of Acquisition Sep. 01, 1972    
Net Rentable Square Feet 150,000    
Depreciation Life 37 years [6]    
Concord Centre [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 413,000 [1]    
Initial Cost, Buildings and Improvements 850,000 [1]    
Net Improvements (Retirement) since Acquisition 3,437,000    
Gross Amounts at Which Carried at December 31, 2011, Land 413,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 4,287,000    
Gross Amounts at Which Carried at December 31, 2011, Total 4,700,000 [2]    
Accumulated Depreciation at December 31, 2011 2,885,000    
Year of Construction Jan. 01, 1960    
Date of Acquisition Dec. 01, 1973    
Net Rentable Square Feet 76,000    
Depreciation Life 33 years [6]    
Wheaton Park [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 796,000 [1]    
Initial Cost, Buildings and Improvements 857,000 [1]    
Net Improvements (Retirement) since Acquisition 4,526,000    
Gross Amounts at Which Carried at December 31, 2011, Land 796,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 5,383,000    
Gross Amounts at Which Carried at December 31, 2011, Total 6,179,000 [2]    
Accumulated Depreciation at December 31, 2011 3,207,000    
Year of Construction Jan. 01, 1967    
Date of Acquisition Sep. 01, 1977    
Net Rentable Square Feet 74,000    
Depreciation Life 50 years [6]    
Bradlee [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,152,000 [1]    
Initial Cost, Buildings and Improvements 5,383,000 [1]    
Net Improvements (Retirement) since Acquisition 8,114,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,152,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 13,497,000    
Gross Amounts at Which Carried at December 31, 2011, Total 17,649,000 [2]    
Accumulated Depreciation at December 31, 2011 9,216,000    
Year of Construction Jan. 01, 1955    
Date of Acquisition Dec. 01, 1984    
Net Rentable Square Feet 168,000    
Depreciation Life 40 years [6]    
Chevy Chase Metro Plaza [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 1,549,000 [1]    
Initial Cost, Buildings and Improvements 4,304,000 [1]    
Net Improvements (Retirement) since Acquisition 4,870,000    
Gross Amounts at Which Carried at December 31, 2011, Land 1,549,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 9,174,000    
Gross Amounts at Which Carried at December 31, 2011, Total 10,723,000 [2]    
Accumulated Depreciation at December 31, 2011 5,698,000    
Year of Construction Jan. 01, 1975    
Date of Acquisition Sep. 01, 1985    
Net Rentable Square Feet 49,000    
Depreciation Life 50 years [6]    
Montgomery Village Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 11,625,000 [1]    
Initial Cost, Buildings and Improvements 9,105,000 [1]    
Net Improvements (Retirement) since Acquisition 3,178,000    
Gross Amounts at Which Carried at December 31, 2011, Land 11,625,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 12,283,000    
Gross Amounts at Which Carried at December 31, 2011, Total 23,908,000 [2]    
Accumulated Depreciation at December 31, 2011 5,139,000    
Year of Construction Jan. 01, 1969    
Date of Acquisition Dec. 01, 1992    
Net Rentable Square Feet 197,000    
Depreciation Life 50 years [6]    
Shoppes of Foxchase [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 5,838,000 [1]    
Initial Cost, Buildings and Improvements 2,979,000 [1]    
Net Improvements (Retirement) since Acquisition 13,135,000    
Gross Amounts at Which Carried at December 31, 2011, Land 5,838,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 16,114,000    
Gross Amounts at Which Carried at December 31, 2011, Total 21,952,000 [2]    
Accumulated Depreciation at December 31, 2011 4,829,000    
Year of Construction Jan. 01, 1960    
Date of Acquisition Jun. 01, 1994    
Net Rentable Square Feet 134,000    
Depreciation Life 50 years [6]    
Frederick County Square [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 6,561,000 [1]    
Initial Cost, Buildings and Improvements 6,830,000 [1]    
Net Improvements (Retirement) since Acquisition 3,169,000    
Gross Amounts at Which Carried at December 31, 2011, Land 6,561,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 9,999,000    
Gross Amounts at Which Carried at December 31, 2011, Total 16,560,000 [2]    
Accumulated Depreciation at December 31, 2011 5,958,000    
Year of Construction Jan. 01, 1973    
Date of Acquisition Aug. 01, 1995    
Net Rentable Square Feet 227,000    
Depreciation Life 30 years [6]    
800 S. Washington Street [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,904,000 [1]    
Initial Cost, Buildings and Improvements 5,489,000 [1]    
Net Improvements (Retirement) since Acquisition 5,992,000    
Gross Amounts at Which Carried at December 31, 2011, Land 2,904,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,481,000    
Gross Amounts at Which Carried at December 31, 2011, Total 14,385,000 [2]    
Accumulated Depreciation at December 31, 2011 3,714,000    
Year of Construction Jan. 01, 1951    
Date of Acquisition Jun. 01, 1998    
Net Rentable Square Feet 47,000    
Depreciation Life 30 years [6]    
Centre at Hagerstown . [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 13,029,000 [1]    
Initial Cost, Buildings and Improvements 25,415,000 [1]    
Net Improvements (Retirement) since Acquisition 2,165,000    
Gross Amounts at Which Carried at December 31, 2011, Land 13,029,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 27,580,000    
Gross Amounts at Which Carried at December 31, 2011, Total 40,609,000 [2]    
Accumulated Depreciation at December 31, 2011 9,815,000    
Year of Construction Jan. 01, 2000    
Date of Acquisition Jun. 01, 2002    
Net Rentable Square Feet 332,000    
Depreciation Life 30 years [6]    
Frederick Crossing [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 12,759,000 [1],[5]    
Initial Cost, Buildings and Improvements 35,477,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 2,127,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 12,759,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 37,604,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 50,363,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 10,319,000 [5]    
Year of Construction Jan. 01, 1999 [5]    
Date of Acquisition Mar. 01, 2005 [5]    
Net Rentable Square Feet 295,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
Randolph Shopping Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 4,928,000 [1]    
Initial Cost, Buildings and Improvements 13,025,000 [1]    
Net Improvements (Retirement) since Acquisition 650,000    
Gross Amounts at Which Carried at December 31, 2011, Land 4,928,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 13,675,000    
Gross Amounts at Which Carried at December 31, 2011, Total 18,603,000 [2]    
Accumulated Depreciation at December 31, 2011 3,366,000    
Year of Construction Jan. 01, 1972    
Date of Acquisition May 01, 2006    
Net Rentable Square Feet 82,000    
Depreciation Life 30 years [6]    
Montrose Shopping Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 11,612,000 [1]    
Initial Cost, Buildings and Improvements 22,410,000 [1]    
Net Improvements (Retirement) since Acquisition 2,529,000    
Gross Amounts at Which Carried at December 31, 2011, Land 11,612,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 24,939,000    
Gross Amounts at Which Carried at December 31, 2011, Total 36,551,000 [2]    
Accumulated Depreciation at December 31, 2011 6,009,000    
Year of Construction Jan. 01, 1970    
Date of Acquisition May 01, 2006    
Net Rentable Square Feet 145,000    
Depreciation Life 30 years [6]    
Gateway Overlook [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 28,816,000 [1]    
Initial Cost, Buildings and Improvements 52,249,000 [1]    
Net Improvements (Retirement) since Acquisition 335,000    
Gross Amounts at Which Carried at December 31, 2011, Land 29,394,000    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 52,006,000    
Gross Amounts at Which Carried at December 31, 2011, Total 81,400,000 [2]    
Accumulated Depreciation at December 31, 2011 5,588,000    
Year of Construction Jan. 01, 2007    
Date of Acquisition Dec. 01, 2010    
Net Rentable Square Feet 223,000    
Depreciation Life 30 years [6]    
Olney Village Center Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 15,842,000 [1],[5]    
Initial Cost, Buildings and Improvements 39,133,000 [1],[5]    
Net Improvements (Retirement) since Acquisition 892,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Land 15,842,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 40,025,000 [5]    
Gross Amounts at Which Carried at December 31, 2011, Total 55,867,000 [2],[5]    
Accumulated Depreciation at December 31, 2011 2,124,000 [5]    
Year of Construction Jan. 01, 1979 [5]    
Date of Acquisition Aug. 01, 2011 [5]    
Net Rentable Square Feet 198,000 [3],[5]    
Depreciation Life 30 years [5],[6]    
3801 Connecticut [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Secured Debt 35,399,000    
Kenmore Apartments [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Mortgage notes payable 35,535,000 36,097,000  
Walker House Apartments [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Secured Debt 16,531,000    
West Gude Drive [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Mortgage notes payable 29,996,000 30,761,000  
Olney Village Center Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Mortgage notes payable 22,343,000 23,873,000  
Bethesda Hill Apartments [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Secured Debt 29,099,000    
John Marshall II Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Mortgage notes payable 53,274,000 53,936,000  
M Street 2445 [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Mortgage notes payable 96,848,000 [9] 95,593,000 [9]  
Ashburn Farm Professional Cntr [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Secured Debt 4,337,000    
Woodholme Medical Center [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Mortgage notes payable $ 19,608,000 $ 19,954,000  
Minimum [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Useful Life 3 years    
Maximum [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Useful Life 50 years    
[1] The purchase cost of real estate investments has been divided between land and buildings and improvements on the basis of management’s determination of the fair values.
[2] At December 31, 2012, total land, buildings and improvements are carried at $2,148,544,000 for federal income tax purposes.
[3] Residential properties are presented in gross square feet.
[4] Includes non-cash accruals for capital items and assumed mortgages.
[5] At December 31, 2012, our properties were encumbered by non-recourse mortgage amounts as follows: $35,399,000 on 3801 Connecticut Avenue, $16,531,000 on Walker House, $29,099,000 on Bethesda Hill, $35,535,000 on The Kenmore, $29,996,000 on West Gude Drive, $96,848,000 on 2445 M Street, $53,274,000 on John Marshall II, $19,608,000 on Woodholme Medical Center, $4,337,000 on Ashburn Farm, and $22,343,000 on Olney Village Center.
[6] The useful life shown is for the main structure. Buildings and improvements are depreciated over various useful lives ranging from 3 to 50 years.
[7] As of December 31, 2012, WRIT had under development via joint venture arrangements, a mid-rise multifamily property in Arlington, Virginia (650 North Glebe) and a high-rise multifamily property in Alexandria, Virginia (1225 First Street). The total value not yet placed into service of these development projects via joint venture arrangements at December 31, 2012 was $35.5 million.
[8] As of December 31, 2012, WRIT had land held for development in Herndon, VA (Dulles Station, Phase II). WRIT also held a 0.8 acre parcel of land at 4661 Kenmore for future development. Additionally, WRIT had investments in various smaller development or redevelopment projects. The total land value not yet placed in service of these development projects at December 31, 2012 was $7.5 million. $0.5 million of Dulles Station, Phase II land was placed into service upon the completion of a portion of the parking garage structure.
[9] Interest only is payable monthly until the maturity date upon which all unpaid principal and interest are payable in full.