Debt and Preferred Equity Investments (Preferred Equity Investments)(Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Preferred equity investment
Aggregate weighted average current yield (as a percent)	9.42%
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 1,627,836	$ 1,640,412
Preferred Equity, March 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	73,448
Carrying Value, Net of Discounts and Deferred Origination Fees	9,986	9,982
Preferred Equity, November 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	58,617
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 37,920	37,893
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	8.36%
Future Funding Obligations	$ 0
Senior Financing	132,065
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 47,906	$ 47,875