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Mortgages Payable (Details) (USD $) |  |  |  |  | 3 Months Ended |  | 3 Months Ended | 0 Months Ended |  |  |  |  | 3 Months Ended |  |
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Mar. 31, 2014 | Dec. 31, 2013 | Mar. 31, 2014 Rego Park 1 Shopping [Member] Mortgages [Member] Secured [Member] | Dec. 31, 2013 Rego Park 1 Shopping [Member] Mortgages [Member] Secured [Member] | Mar. 31, 2014 Rego Park 2 Property [Member] Mortgages [Member] Secured [Member] | Dec. 31, 2013 Rego Park 2 Property [Member] Mortgages [Member] Secured [Member] | Mar. 31, 2014 Lexington Avenue Property [Member] | Feb. 28, 2014 Lexington Avenue Property [Member] Mortgages [Member] Secured [Member] Office Space [Member] Extensions | Mar. 31, 2014 Lexington Avenue Property [Member] Mortgages [Member] Secured [Member] Office Space [Member] | Dec. 31, 2013 Lexington Avenue Property [Member] Mortgages [Member] Secured [Member] Office Space [Member] | Mar. 31, 2014 Lexington Avenue Property [Member] Mortgages [Member] Secured [Member] Retail Space [Member] | Dec. 31, 2013 Lexington Avenue Property [Member] Mortgages [Member] Secured [Member] Retail Space [Member] | Mar. 31, 2014 Lexington Avenue Property [Member] Mortgages [Member] Secured [Member] Retail Space [Member] Maximum [Member] | Mar. 31, 2014 Paramus Property [Member] Mortgages [Member] Secured [Member] | Dec. 31, 2013 Paramus Property [Member] Mortgages [Member] Secured [Member]
Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of cash mortgage collateralized |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument Maturity Date String |  |  | 2015-03 |  | 2018-11 |  |  |  | 2021-03 |  | 2015-07 |  |  | 2018-10 |
Interest rate (in percentage) |  |  | 0.40% |  | 2.00% |  |  |  | 1.11% |  | 4.93% |  |  | 2.90% |
Balance | $ 1,035,022,000 | $ 1,049,959,000 | $ 78,246,000 | $ 78,246,000 | $ 268,776,000 | $ 269,496,000 | $ 320,000,000 |  | $ 300,000,000 | $ 314,217,000 | $ 320,000,000 | $ 320,000,000 |  | $ 68,000,000 | $ 68,000,000
Basis spread over LIBOR (in percentage) |  |  |  |  | 1.85% |  |  | 0.95% |  |  |  |  |  |  |
Mortgage Loan Converted To Recourse |  |  |  |  |  |  | 75,000,000 |  |  |  |  |  | 75,000,000 |  |
Proceeds from (Repayments of) Debt |  |  |  |  |  |  |  | 300,000,000 |  |  |  |  |  |  |
Number Of Extensions Available (Extensions) |  |  |  |  |  |  |  | 4 |  |  |  |  |  |  |
Length Of Extension Available |  |  |  |  |  |  |  | 1 year |  |  |  |  |  |  |
Derivative Notional Amount |  |  |  |  |  |  |  | $ 300,000,000 |  |  |  |  |  |  |
Derivative cap interest rate, LIBOR |  |  |  |  |  |  |  | 6.00% |  |  |  |  |  |  |

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- Definition The term of the extension available, in years. + References No definition available. + Details
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- Definition Amount of loan that will become recourse in case of a substantial casualty + References No definition available. + Details
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- Definition Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer. + 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 SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 3: 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 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 13, 16 -Article 9 + Details
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- Definition The net cash inflow or outflow in aggregate debt due to repayments and proceeds from additional borrowings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 + Details
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