VARIABLE INTEREST ENTITIES LOANS HELD FOR INVESTMENT (Summary of Loans) (Details) RSO (USD $)	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Dec. 31, 2012 RSO [Member] Loan	Dec. 31, 2011 RSO [Member]	Dec. 31, 2010 RSO [Member]	Dec. 31, 2012 RSO [Member] Bank Loans [Member]	Dec. 31, 2011 RSO [Member] Bank Loans [Member]	Dec. 31, 2012 RSO [Member] Whole Loans [Member]	Dec. 31, 2012 RSO [Member] Commercial Real Estate Loans [Member]	Dec. 31, 2011 RSO [Member] Commercial Real Estate Loans [Member]	Dec. 31, 2012 RSO [Member] Commercial Real Estate Loans [Member] Whole Loans [Member]	Dec. 31, 2011 RSO [Member] Commercial Real Estate Loans [Member] Whole Loans [Member]	Dec. 31, 2012 RSO [Member] Commercial Real Estate Loans [Member] B Notes [Member]	Dec. 31, 2011 RSO [Member] Commercial Real Estate Loans [Member] B Notes [Member]	Dec. 31, 2012 RSO [Member] Commercial Real Estate Loans [Member] Mezzanine Loans [Member]	Dec. 31, 2011 RSO [Member] Commercial Real Estate Loans [Member] Mezzanine Loans [Member]
Receivables with Imputed Interest [Line Items]
Principal, Gross					$ 1,887,825,000	$ 1,836,075,000		$ 1,218,563,000	$ 1,205,826,000		$ 669,262,000	$ 630,249,000	$ 569,829,000	$ 545,828,000	$ 16,441,000	$ 16,579,000	$ 82,992,000	$ 67,842,000
Unamortized (discount) premium, gross					(27,460,000)	(33,340,000)		(25,249,000)	(32,073,000)		(2,211,000)	(1,267,000)	(1,891,000)	(1,155,000)	(114,000)	(144,000)	(206,000)	32,000
Gross carrying value of loans held for investment					1,860,365,000	1,802,735,000		1,193,314,000	1,173,753,000		667,051,000	628,982,000	567,938,000	544,673,000	16,327,000	16,435,000	82,786,000	67,874,000
Allowance for loan loss	(27,613,000)	(10,935,000)	(2,024,000)	(4,795,000)	(17,691,000)	(27,518,000)	(34,303,000)
Unamortized (discount) premium, gross, allowance for loan loss					0	0
Carrying value, allowance for loan loss					(17,691,000)	(27,518,000)
Principal, Net					1,870,134,000	1,808,557,000
Unamortized (discount) premium, net					(27,460,000)	(33,340,000)
Net carrying value of loans held for investment					1,842,674,000	1,775,217,000
Deferred amendment fees					450,000	286,000
Deferred upfront fee								334,000	0
Loan origination fees											1,900,000	984,000
Extension and exit fees											214,000	123,000
Loans held for sale, investment in debt and equity securities					14,900,000	3,200,000
Loans held for sale, net					$ 48,894,000	$ 3,154,000		$ 1,200,000,000	$ 1,200,000,000	$ 34,000,000
Number of loans held for sale					2