Quarterly report pursuant to Section 13 or 15(d)

Real Estate - Schedule of Assets Acquired (Details)

v3.7.0.1
Real Estate - Schedule of Assets Acquired (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Real Estate [Line Items]    
Payments to Acquire Real Estate $ 138,371 $ 227,413
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned 376  
Watergate 600 [Member]    
Real Estate [Line Items]    
Payments to Acquire Land 45,981  
Payments to Acquire Building 66,241  
Tenant origination costs 12,084  
Leasing commissions absorption costs 23,161  
Net lease intangible assets 498  
Net lease intangible liabilities (9,585)  
Deferred tax liability $ (560)  
Watergate 600 [Member] | Tenant Origination Costs [Member]    
Real Estate [Line Items]    
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life 92 months  
Watergate 600 [Member] | Leasing Commissions Absorption Costs [Member]    
Real Estate [Line Items]    
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life 84 months  
Watergate 600 [Member] | Net lease intangible assets [Member]    
Real Estate [Line Items]    
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life 19 months  
Watergate 600 [Member] | Net lease intangible liability [Member]    
Real Estate [Line Items]    
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life 97 months  
Series of Individually Immaterial Business Acquisitions [Member]    
Real Estate [Line Items]    
Real Estate Investment Property, at Cost, Net of Adjustments $ 137,820  
Series of Individually Immaterial Business Acquisitions [Member] | Watergate 600 [Member]    
Real Estate [Line Items]    
Real Estate Investment Property, at Cost, Net of Adjustments 135,000  
Business acquisition, transaction costs 2,800  
Other Payments to Acquire Businesses $ 1,000  
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares 12,124  
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned $ 400 $ 0
Duration for average share price valuation (in days) 20 days