Investment in 111 West 57th Partners LLC, Summary (Details) - Investment in 111 West 57th Partners LLC [Member] $ in Thousands	Jun. 28, 2013 USD ($)
Initial Investment Relating to the 111 West 57th Property [Abstract]
Company's aggregate initial investment	$ 57,250
Company's aggregate initial membership interest %	60.30%

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481687/323-10-50-3

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant