Debt and Preferred Equity Investments (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Preferred equity investment
Aggregate weighted average current yield (as a percent)	10.33%
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 1,408,804		$ 1,304,839
Preferred Equity, July 2015
Preferred equity investment
Senior Financing	550,000	[1]
Carrying Value, Net of Discounts and Deferred Origination Fees	123,041	[1],[2]	115,198	[1],[2]
Preferred Equity, November 2017
Preferred equity investment
Senior Financing	70,000
Carrying Value, Net of Discounts and Deferred Origination Fees	9,954	[2]	9,940	[2]
Preferred Equity, Repaid April 2014
Preferred equity investment
Senior Financing	0	[3]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[2],[3]	25,896	[2],[3]
Preferred Equity, Repaid November 2014
Preferred equity investment
Senior Financing	0	[1],[4]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[2],[4]	218,330	[1],[2],[4]
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	10.89%
Senior Financing	620,000
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 132,995	[2]	$ 369,364	[2]

[1] The difference between the pay and accrual rates is included as an addition to the principal balance outstanding.

[2] Carrying value is net of discounts and deferred origination fees.

[3] This preferred equity investment was redeemed in April 2014.

[4] This preferred equity investment was redeemed in November 2014.