Investment in Unconsolidated Joint Ventures Investment in Unconsolidated Joint Ventures-Additional Information (Details) (USD $)	3 Months Ended								12 Months Ended			0 Months Ended	1 Months Ended								12 Months Ended			1 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 27-29 West 34th Street	Jul. 31, 2012 One Court Square	Apr. 30, 2012 379 West Broadway	Mar. 31, 2012 141 Fifth Avenue	Nov. 30, 2011 33 West 450 Street	Aug. 31, 2011 1551 to 1555 Broadway	Jun. 30, 2012 717 Fifth Avenue	Dec. 31, 2013 717 Fifth Avenue		Dec. 31, 2013 Joint venture	Dec. 31, 2012 Joint venture	Dec. 31, 2010 Joint venture	Aug. 31, 2012 The Meadows Joint venture
Investment in Unconsolidated Joint Ventures
Beneficial interest sold (as a percent)												50.00%					10.00%	50.00%
Consideration for sale of beneficial interest in real estate property												$ 70,100,000					$ 9,700,000
Mortgage loan related to property sales												52,800,000
Sales price													481,100,000	48,500,000	46,000,000			617,600,000
Mortgage assigned to joint venture									0	0	30,000,000		315,000,000
Equity in net gain on sale of interest in unconsolidated joint venture/ real estate	7,538,000	(354,000)	(3,583,000)	0	19,277,000	(4,807,000)	15,323,000	7,260,000	3,601,000	37,053,000	2,918,000	7,600,000	1,000,000	6,500,000	7,300,000		4,000,000	3,000,000
Accrued employee compensation award												1,500,000
Fees position acquired														13,500,000
Employee compensation award															1,500,000			1,000,000
Remaining percentage of interest acquired in joint venture (percent)																50.00%
Ownership Interest (as a percent)																100.00%			10.92%	[1]
Management fees, base revenue																					4,700,000	7,900,000	8,600,000
Cash income recognized on distribution																		67,900,000
Gain on early extinguishment of debt																								$ 10,800,000

[1] In June 2012, this retail condominium was recapitalized. The recapitalization triggered a promote to our partner, which resulted in a reduction of our economic interest. In addition, we sold 50% of our remaining interest at a property valuation of $617.6 million. We recognized $67.9 million of additional cash income, equivalent to profit, due to the distribution of refinancing proceeds and a gain on sale of $3.0 million, which is net of a $1.0 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale.