Debt and Preferred Equity Investments (Preferred Equity Investments)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Preferred equity investment
Mortgage Loans on Real Estate, Interest Rate	9.34%
Carrying Value	$ 1,640,412	$ 1,670,020
Preferred Equity with an Initial Mandatory Redemption Date of March 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	71,486
Carrying Value	9,982	9,967
Preferred Equity with an Initial Mandatory Redemption Date of November 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	58,786
Carrying Value	$ 37,893	32,209
Preferred equity investments
Preferred equity investment
Mortgage Loans on Real Estate, Interest Rate	8.16%
Future Funding Obligations	$ 0
Senior Financing	130,272
Carrying Value	$ 47,875	$ 42,176