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Investments in Unconsolidated Joint Ventures Investments in Unconsolidated Joint Ventures (Narrative) (Details) $ in Thousands | Apr. 11, 2016 USD ($) ft² yr | Apr. 04, 2016 USD ($) ft² yr | Jun. 30, 2016 USD ($) | Dec. 31, 2015 USD ($)
--- | --- | --- | --- | ---
Schedule of Equity Method Investments [Line Items] |  |  |  |
Secured Debt |  |  | $ 3,189,013 | $ 3,435,242
Construction Loans [Member] | Annapolis Junction Building Seven [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Ownership Percentage |  | 50.00% |  |
Construction Loan |  | $ 21,500 |  |
Construction Loan Facility Borrowing Capacity |  | $ 22,000 |  |
Debt Instrument, Basis Spread on Variable Rate |  | 1.65% |  |
Number of extensions |  | 1 |  |
Extension Option (in years) | yr |  | 1 |  |
Net Rentable Area (in sf) | ft² |  | 127,000 |  |
Secured Debt [Member] | Annapolis Junction Buidling One [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Ownership Percentage | 50.00% |  |  |
Secured Debt | $ 39,900 |  |  |
Debt Instrument, Basis Spread on Variable Rate | 1.75% |  |  |
Number of extensions | 1 |  |  |
Extension Option (in years) | yr | 3 |  |  |
Net Rentable Area (in sf) | ft² | 118,000 |  |  |

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- Definition This element represents the carrying value of a short-term real estate loan to finance building costs. The funds are disbursed as needed or in accordance with a prearranged plan; generally, a portion of the funds is disbursed at inception and the remainder as construction progresses. The money is repaid on completion of the project, usually from the proceeds of a mortgage loan. The rate is normally higher than the prime rate, and there is usually an origination fee. The effective yield on these loans tends to be high, and the lender has a security interest in the real property. Note that there are separate concepts for the current and noncurrent portions of long-term construction loans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20 -Article 5 + Details
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- Definition Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
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