Loans and Other Lending Investments, net (Details 5) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jun. 30, 2011 Nonperforming assets	Dec. 31, 2011 Nonperforming assets	Dec. 31, 2011 Senior mortgages	Dec. 31, 2010 Senior mortgages	Dec. 31, 2009 Senior mortgages	Dec. 31, 2011 Subordinate mortgages	Dec. 31, 2010 Subordinate mortgages	Dec. 31, 2009 Subordinate mortgages	Dec. 31, 2011 Corporate/Partnership loans	Dec. 31, 2010 Corporate/Partnership loans	Dec. 31, 2009 Corporate/Partnership loans	Dec. 31, 2011 With no related allowance recorded	Dec. 31, 2010 With no related allowance recorded	Dec. 31, 2009 With no related allowance recorded	Dec. 31, 2011 With no related allowance recorded Senior mortgages	Dec. 31, 2010 With no related allowance recorded Senior mortgages	Dec. 31, 2009 With no related allowance recorded Senior mortgages	Dec. 31, 2010 With no related allowance recorded Subordinate mortgages	Dec. 31, 2009 With no related allowance recorded Subordinate mortgages	Dec. 31, 2011 With no related allowance recorded Corporate/Partnership loans	Dec. 31, 2010 With no related allowance recorded Corporate/Partnership loans	Dec. 31, 2009 With no related allowance recorded Corporate/Partnership loans	Dec. 31, 2011 With an allowance recorded	Dec. 31, 2010 With an allowance recorded	Dec. 31, 2009 With an allowance recorded	Dec. 31, 2011 With an allowance recorded Senior mortgages	Dec. 31, 2010 With an allowance recorded Senior mortgages	Dec. 31, 2009 With an allowance recorded Senior mortgages	Dec. 31, 2011 With an allowance recorded Subordinate mortgages	Dec. 31, 2010 With an allowance recorded Subordinate mortgages	Dec. 31, 2009 With an allowance recorded Subordinate mortgages	Dec. 31, 2011 With an allowance recorded Corporate/Partnership loans	Dec. 31, 2010 With an allowance recorded Corporate/Partnership loans	Dec. 31, 2009 With an allowance recorded Corporate/Partnership loans
Investment in impaired loans
Recorded Investment	$ 1,583,631,000	$ 2,313,444,000				$ 1,488,450,000	$ 2,238,869,000		$ 22,480,000			$ 72,701,000	$ 74,575,000		$ 229,598,000	$ 414,971,000		$ 219,488,000	$ 404,861,000				$ 10,110,000	$ 10,110,000		$ 1,354,033,000	$ 1,898,473,000		$ 1,268,962,000	$ 1,834,008,000		$ 22,480,000			$ 62,591,000	$ 64,465,000
Unpaid Principal Balance	1,577,370,000	2,304,355,000				1,481,807,000	2,229,276,000		22,558,000			73,005,000	75,079,000		228,772,000	414,286,000		218,612,000	404,126,000				10,160,000	10,160,000		1,348,598,000	1,890,069,000		1,263,195,000	1,825,150,000		22,558,000			62,845,000	64,919,000
Related Allowance	(573,124,000)	(694,425,000)				(540,670,000)	(683,948,000)		(22,480,000)			(9,974,000)	(10,477,000)													(573,124,000)	(694,425,000)		(540,670,000)	(683,948,000)		(22,480,000)			(9,974,000)	(10,477,000)
Loans modified through troubled debt restructurings	255,300,000	294,300,000
Average Recorded Investment	2,013,239,000	3,242,058,000	4,288,572,000			1,917,565,000	3,070,885,000	4,091,379,000	19,477,000	78,529,000	67,962,000	76,197,000	92,644,000	129,231,000	319,189,000	688,080,000	782,917,000	309,079,000	659,150,000	751,011,000	1,404,000	2,953,000	10,110,000	27,526,000	28,953,000	1,694,050,000	2,553,978,000	3,505,655,000	1,608,486,000	2,411,735,000	3,340,368,000	19,477,000	77,125,000	65,009,000	66,087,000	65,118,000	100,278,000
Interest Income Recognized	39,998,000	27,717,000	14,223,000			38,986,000	25,655,000	13,827,000		194,000	396,000	1,012,000	1,868,000		32,479,000	22,427,000	10,511,000	31,799,000	20,472,000	10,115,000	87,000	396,000	680,000	1,868,000		7,519,000	5,290,000	3,712,000	7,187,000	5,183,000	3,712,000		107,000		332,000
Interest Income Recognized				$ 26,300,000	$ 26,300,000