VARIABLE INTEREST ENTITIES LOANS HELD FOR INVESTMENT (Weighted Average Life of Commercial Real Estate Loans, at Amortized Cost) (Details) RSO - RSO [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Middle-market Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less than one year	$ 0	$ 0
Loans held for investment, amortized cost	349,471	250,113
Greater than one year and less than five years	210,773	132,353
Five years or greater	138,698	117,760
Bank Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less than one year	2,518	7,829
Loans held for investment, amortized cost	152,627	330,930
Greater than one year and less than five years	145,216	274,332
Five years or greater	4,893	48,769
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2014	0	0
2015	77,599	60,473
2016 and Thereafter	1,587,137	1,286,557
Loans held for investment, amortized cost	1,664,736	1,347,030
Commercial Real Estate Loans [Member] | Whole Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2014	0	0
2015	39,527	27,665
2016 and Thereafter	1,563,858	1,235,927
Loans held for investment, amortized cost	1,603,385	1,263,592
Commercial Real Estate Loans [Member] | Mezzanine Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2014	0	0
2015	38,072	16,736
2016 and Thereafter	7,315	50,630
Loans held for investment, amortized cost	45,387	67,366
Commercial Real Estate Loans [Member] | B Notes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
2014	0	0
2015	0	16,072
2016 and Thereafter	15,964	0
Loans held for investment, amortized cost	$ 15,964	$ 16,072