Debt and Preferred Equity Investments (Preferred Equity Investments)(Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Preferred equity investment
Aggregate weighted average current yield (as a percent)	9.29%
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 1,453,234	$ 1,670,020
Preferred Equity, March 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	71,486
Carrying Value, Net of Discounts and Deferred Origination Fees	9,978	9,967
Preferred Equity, November 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	59,034
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 37,867	32,209
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	7.32%
Future Funding Obligations	$ 0
Senior Financing	130,520
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 47,845	$ 42,176