Investment in 111 West 57th Partners LLC (Details) (USD $)	3 Months Ended
	Mar. 31, 2014 Agreements sqft	Dec. 31, 2013
Investment in 111 West 57th Partners LLC [Abstract]
Amount of the investment	$ 56,000,000
Percentage ownership (in hundredths)	59.00%
Additional indirect contribution	1,250,000
Additional ownership acquired through indirect contribution (in hundredths)	1.30%
Additional contributions made by other partners in the agreement	37,750,000
Description of partnership agreement distribution	The JV Agreement and related operating agreements generally provide that all distributable cash shall be distributed as follows: (i) first, 100% to the members in proportion to their percentage interests until Investment LLC has received distributions yielding a 20% internal rate of return as calculated; (ii) second, 100% to the Sponsor as a return of (but not a return on) any additional capital contributions made by the Sponsor on account of manager overruns; and (iii) thereafter, (a) 50% to the members in proportion to their respective percentage interests at the time of such distribution, and (b) fifty percent 50% to the Sponsor.
Cost for inclusionary zoning rights	6,500,000
Area of Real Estate Property	346,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	867,000
Subordinated participation interest to CEO (in hundredths)	10.00%
Percentage of distribution on company's initial investment to be received prior to CEO receiving percentage distribution (in hundredths)	150.00%
Initial aggregate investment in Investment LLC	57,250,000
Percentage of outstanding shares to be owned by CEO, minimum (in hundredths)	20.00%
Number of purchase agreements	3
Additional deposit made by Joint Venture for purchase of additional inclusionary zoning rights	1,800,000
Additional capital the Company contributed to Joint Venture for deposit into inclusionary air rights reserve in March 2014	1,072,000
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Real estate held for development, net	273,318,000	263,312,000
Escrow deposits	36,636,000	43,100,000
Other assets	15,987,000	18,062,000
Total assets	325,941,000	324,474,000
Equity Method Investment, Summarized Financial Information, Liabilities [Abstract]
Mortgage payable	230,000,000	230,000,000
Other liabilities	3,431,000	2,767,000
Total liabilities	233,431,000	232,767,000
Equity:
Total equity	92,510,000	91,707,000
Total liabilities and equity	325,941,000	324,474,000
Income (Loss) [Abstract]
Rental income	273,000
Expenses	1,270,000
Net income (loss)	$ (997,000)