v2.4.0.8

Investments in Unconsolidated Joint Ventures investment in Unconsolidated Joint Ventures (Narrative) (Details) (USD $) | 9 Months Ended | 0 Months Ended |  | 0 Months Ended |  |
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Sep. 30, 2014 | Sep. 30, 2013 | Apr. 10, 2014 501 K Street [Member] sqft | Sep. 30, 2014 501 K Street [Member] payments sqft | Jun. 23, 2014 Annapolis Junction Building Eight [Member] Y | Apr. 30, 2014 Annapolis Junction Building Eight [Member] sqft | Apr. 10, 2014 joint venture partner [Member] 501 K Street [Member] | Apr. 10, 2014 Company [Member] 501 K Street [Member] | Apr. 30, 2014 Company [Member] Annapolis Junction Building Eight [Member]
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Description of Variable Rate Basis |  |  |  |  |  | LIBOR plus 1.50% |  |  |  |
Capital contributions to unconsolidated joint ventures | $ 47,767,000 | $ 0 | $ 39,000,000 |  |  |  | $ 5,400,000 |  |  |
Ownership Percentage |  |  |  | 50.00% | [1] |  |  | 50.00% | 50.00% | 50.00%
Net Rentable Area (in sf) |  |  | 520,000 |  |  |  | 125,000 |  |  |
Construction Loan Facility Borrowing Capacity |  |  |  |  |  | $ 26,000,000 |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 1.50% |  |  |  |
Maturity Date |  |  |  |  |  | Jun. 23, 2017 |  |  |  |
Number of extensions |  |  |  |  |  | 2 |  |  |  |
Extension Option (in years) |  |  |  |  |  | 1 |  |  |  |
Potential additonal payments to joint venture partner |  |  |  | 2 |  |  |  |  |  |
Minimum square footage to make a potential additional payment to joint venture partner (in sqft) |  |  |  | 520,000 |  |  |  |  |  |
[1] | Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

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- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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