Debt and Preferred Equity Investments (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Preferred equity investments	Dec. 31, 2012 Preferred equity investments	Mar. 31, 2013 Preferred equity with initial mandatory redemption on July, 2014	Dec. 31, 2012 Preferred equity with initial mandatory redemption on July, 2014	Feb. 29, 2012 Preferred equity with initial mandatory redemption on July, 2014	Mar. 31, 2013 Preferred equity with initial mandatory redemption of October 2014	Dec. 31, 2012 Preferred equity with initial mandatory redemption of October 2014	Mar. 31, 2013 Preferred equity with initial mandatory redemption on April, 2016	Dec. 31, 2012 Preferred equity with initial mandatory redemption on April, 2016	Mar. 31, 2013 Preferred equity with initial mandatory redemption on July, 2016	Dec. 31, 2012 Preferred equity with initial mandatory redemption on July, 2016
Preferred equity investment
Aggregate weighted average current yield (as a percent)	11.10%	11.40%
Senior Financing	$ 4,073,528,000	$ 1,533,347,000		$ 480,000,000			$ 70,000,000		$ 57,087,000		$ 926,260,000
Carrying Value, Net of Discounts		346,607,000	340,885,000	103,437,000	100,831,000		10,000,000	10,000,000	20,238,000	19,136,000	212,932,000	210,918,000
Junior preferred equity loan						50,000,000
Committed additional capital contribution funded									$ 5,700,000