Quarterly report pursuant to Section 13 or 15(d)

Real Estate - Variable Interest Entities (Details)

v2.4.0.8
Real Estate - Variable Interest Entities (Details) (USD $)
9 Months Ended 1 Months Ended 3 Months Ended 9 Months Ended 1 Months Ended 9 Months Ended 9 Months Ended 0 Months Ended
Sep. 30, 2014
Dec. 31, 2013
Jun. 30, 2011
650 North Glebe Road [Member]
Sep. 30, 2013
650 North Glebe Road [Member]
Sep. 30, 2014
650 North Glebe Road [Member]
Dec. 31, 2013
650 North Glebe Road [Member]
Nov. 30, 2011
1225 First Street [Member]
Sep. 30, 2014
1225 First Street [Member]
Dec. 31, 2013
1225 First Street [Member]
Sep. 30, 2014
650 N Glebe [Member] [Domain]
extension_option
Dec. 31, 2013
650 N Glebe [Member] [Domain]
Feb. 21, 2013
650 N Glebe [Member] [Domain]
Feb. 21, 2013
London Interbank Offered Rate (LIBOR) [Member]
Secured Debt [Member]
Maximum
650 N Glebe [Member] [Domain]
Feb. 21, 2013
London Interbank Offered Rate (LIBOR) [Member]
Secured Debt [Member]
Minimum [Member]
650 N Glebe [Member] [Domain]
Real Estate Properties [Line Items]                            
Long-term Construction Loan                       $ 33,000,000    
Estimated development costs     49,900,000       95,300,000              
Percentage of capital contribution through debt 70.00%     70.00%       70.00%            
Variable interest entity, qualitative or quantitative information, ownership percentage         90.00%     95.00%            
Percentage of residential property to be leased to achieve project stabilization stage         90.00%                  
Noncontrolling interest, ownership percentage by noncontrolling owners         10.00%     5.00%            
Land and capitalized development costs related to joint ventures         47,084,000 27,343,000   20,807,000 20,788,000          
Accounts payable and accrued liabilities related to joint ventures         6,253,000 1,785,000   76,000 39,000          
Mortgage notes payable $ 413,330,000 $ 294,671,000               $ 21,400,000 $ 7,300,000      
Debt Instrument, Basis Spread on Variable Rate                         2.15% 2.00%
Number of Extension Options                   2        
Debt Agreement Optional Extension Period Exercisable by Option                   1 year