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v3.3.1.900

Investment in unconsolidated Joint Ventures (Narrative) (Details) $ in Thousands |  |  |  | 3 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 26, 2015 USD ($) ft² yr | May. 08, 2015 USD ($) ft² yr | May. 31, 2013 partners | Sep. 30, 2015 USD ($) ft² | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($) | Dec. 22, 2015 ft² | Oct. 22, 2015 ft² | Sep. 22, 2015 ft²
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  | $ 38,207 | $ 52,052 | $ 0 |  |  |
Gains (losses) from early extinguishments of debt |  |  |  |  | (22,040) | (10,633) | 122 |  |  |
Repayments of Secured Debt |  |  |  |  | 54,801 | 87,758 | 80,311 |  |  |
Gain on consolidation of joint ventures |  |  |  |  | $ 0 | $ 0 | $ 385,991 |  |  |
1265 Main Office JV LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  | 50.00% |  |  |  |  |
Net Rentable Area | ft² |  | 115,000 |  |  |  |  |  |  |  |
Term of Lease Signed (in years) | yr |  | 15 |  |  |  |  |  |  |  |
Portion of Building Leased (percentage) |  | 100.00% |  |  |  |  |  |  |  |
767 Fifth Avenue (the General Motors Building) |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of Joint Venture Partners | partners |  |  | 2 |  |  |  |  |  |  |
Annapolis Junction Building Eight [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  | 50.00% |  |
Net Rentable Area | ft² |  |  |  |  |  |  |  | 126,000 |  |
Annapolis Junction Building Seven [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Net Rentable Area | ft² |  |  |  |  |  |  |  |  |  | 127,000
BNY Tower Holdings LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  | 50.00% |  |  |  |  |
Net Rentable Area | ft² | 670,000 |  |  |  |  |  |  |  |  |
Term of Lease Signed (in years) | yr | 20 |  |  |  |  |  |  |  |  |
Square Footage Of Signed Lease | ft² | 222,000 |  |  |  |  |  |  |  |  |
BNY Tower Holdings [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Non refundable option payment | $ 1,000 |  |  |  |  |  |  |  |  |
Annapolis Junction Building Six [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Net Rentable Area | ft² |  |  |  | 119,000 |  |  |  |  |  |
Construction Loan Facility Borrowing Capacity |  |  |  | $ 15,900 |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  | 2.25% |  |  |  |  |  |
Construction Loan |  |  |  | $ 13,400 |  |  |  |  |  |
Hub on Causeway [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  | 50.00% |
Net Rentable Area | ft² |  |  |  |  |  |  |  |  | 385,000 |
joint venture partner [Member] | 1265 Main Office JV LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  | $ 9,400 |  |  |  |  |  |  |  |
joint venture partner [Member] | BNY Tower Holdings LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage | 50.00% |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments | $ 9,100 |  |  |  |  |  |  |  |  |
Company [Member] | 1265 Main Office JV LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |  |  |  |  |
Company [Member] | Annapolis Junction Building Seven [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  |  |  |  |  |  |  | 50.00%
Company [Member] | BNY Tower Holdings LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage | 50.00% |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments | $ 9,100 |  |  |  |  |  |  |  |  |
Company [Member] | Annapolis Junction Building Six [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership Percentage |  |  |  | 50.00% |  |  |  |  |  |
Maximum [Member] | BNY Tower Holdings LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ground Lease Term (in years) | yr | 96 |  |  |  |  |  |  |  |  |
Maximum [Member] | BNY Tower Holdings [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Net Rentable Area | ft² | 1,000,000 |  |  |  |  |  |  |  |  |
Maximum [Member] | Company [Member] | 1265 Main Office JV LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  | $ 9,400 |  |  |  |  |  |  |  |
Minimum [Member] | BNY Tower Holdings LLC [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Ground Lease Term (in years) | yr | 46 |  |  |  |  |  |  |  |  |
Minimum [Member] | BNY Tower Holdings [Member] |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Net Rentable Area | ft² | 600,000 |  |  |  |  |  |  |  |  |

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