Debt and Preferred Equity Investments (Details 4) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 segment	Jun. 30, 2011	Dec. 31, 2011 segment receivables
Debt and Preferred Equity Investments
Number of portfolio segments of financial receivables			1		1
Additional amount of financing receivables included in other assets	$ 119,900,000		$ 119,900,000		$ 108,700,000
Nonaccrual balance of financing receivables	25,100,000		25,100,000		102,600,000
Recorded investment for financing receivables past due 90 days					17,300,000
Number of financing receivables past due 90 days					2
Impaired loans, including non-accrual loans
Unpaid Principal Balance	66,112,000		66,112,000		192,744,000
Recorded Investment	61,466,000		61,466,000		164,853,000
Allowance Allocated	41,050,000		41,050,000		50,175,000
Average recorded investment in impaired loans	69,932,000	201,991,000	74,935,000	223,376,000
Investment and preferred equity income recognized	2,333,000	1,551,000	3,895,000	6,361,000
With no related allowance recorded
Impaired loans, including non-accrual loans
Unpaid Principal Balance					106,623,000
Recorded Investment					83,378,000
With an allowance recorded
Impaired loans, including non-accrual loans
Unpaid Principal Balance	66,112,000		66,112,000		86,121,000
Recorded Investment	61,466,000		61,466,000		81,475,000
Allowance Allocated	$ 41,050,000		$ 41,050,000		$ 50,175,000