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Related Party Transactions (Fees to Vornado) (Details) - Vornado - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Summary of fees to Vornado |  |  |
Fees to related party | $ 8,772 | $ 14,428 | $ 11,799
Company management fees |  |  |
Summary of fees to Vornado |  |  |
Fees to related party | 2,800 | 2,800 | 2,800
Development fees |  |  |
Summary of fees to Vornado |  |  |
Fees to related party | 29 | 194 | 2,435
Leasing fees |  |  |
Summary of fees to Vornado |  |  |
Fees to related party | 1,829 | 7,401 | 2,950
Property management fees and payments for cleaning, engineering and security services |  |  |
Summary of fees to Vornado |  |  |
Fees to related party | $ 4,114 | $ 4,033 | $ 3,614

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- Definition Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 + Details
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