Debt and Preferred Equity Investments (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Loan loss reserve activity
Balance at beginning of year	$ 7,000	$ 50,175	$ 50,175
Expensed	0	3,000	3,000
Recoveries		(2,400)	(2,436)
Charge-offs and reclassifications			(43,739)
Balance at end of period	$ 7,000		$ 7,000