Debt and Preferred Equity Investments (Rollforward of Total Allowance for Loan Loss Reserves)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loan loss reserve activity
Balance at beginning of year	$ 0	$ 0	$ 1,000
Expensed	0	0	0
Recoveries	0	0	0
Charge-offs and reclassifications	0	0	(1,000)
Balance at end of year	$ 0	$ 0	$ 0