VARIABLE INTEREST ENTITIES - FINANCING RECEIVABLES (Loan Portfolio Aging Analysis as of the Dates Indicated at Cost Basis) (Details) RSO (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
90-180 Days Past Due	$ 2,339	$ 1,257
Total Past Due	37,076	62,849
Current	10,305	4,394
RSO [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	443	234
60-89 Days	82	91
90-180 Days Past Due	1,469	3,822
Total Past Due	1,994	4,147
Current	2,041,612	1,408,068
Total Loans Receivable	2,043,606	1,412,215
Total Loans Greater Than 90 days and accruing	0	0
Loans and receivables	1,935,793	1,377,037
Loans Receivable Held-for-sale, Amount	111,736	21,916
RSO [Member] | Whole Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
90-180 Days Past Due	0	0
Total Past Due	0	0
Current	1,263,592	745,789
Total Loans Receivable	1,263,592	745,789
Total Loans Greater Than 90 days and accruing	0
Loans and receivables	1,263,592	745,789
RSO [Member] | B Notes [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
90-180 Days Past Due	0	0
Total Past Due	0	0
Current	16,072	16,205
Total Loans Receivable	16,072	16,205
Total Loans Greater Than 90 days and accruing	0	0
Loans and receivables	16,072	16,205
RSO [Member] | Mezzanine Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
90-180 Days Past Due	0	0
Total Past Due	0	0
Current	67,366	64,317
Total Loans Receivable	67,366	64,317
Total Loans Greater Than 90 days and accruing	0	0
Loans and receivables	67,366	64,317
RSO [Member] | Bank Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
90-180 Days Past Due	1,350	3,554
Total Past Due	1,350	3,554
Current	329,580	514,216
Total Loans Receivable	330,930	517,770
Total Loans Greater Than 90 days and accruing	0	0
Loans and receivables	330,930	517,770
RSO [Member] | Middle-market Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
90-180 Days Past Due	0	0
Total Past Due	0	0
Current	250,113	44,253
Total Loans Receivable	250,113	44,253
Total Loans Greater Than 90 days and accruing		0
Loans and receivables	250,113	44,253
RSO [Member] | Residential Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	443	234
60-89 Days	82	91
90-180 Days Past Due	119	268
Total Past Due	644	593
Current	113,612	16,322
Total Loans Receivable	114,256	16,915
Total Loans Greater Than 90 days and accruing	0	0
Loans Receivable Held-for-sale, Amount	111,454	15,066
RSO [Member] | Loans Receivable - Related Party [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
90-180 Days Past Due	0	0
Total Past Due	0	0
Current	1,277	6,966
Total Loans Receivable	1,277	6,966
Total Loans Greater Than 90 days and accruing	0	0
Held for Sale [Member] | RSO [Member] | Whole Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and receivables	0	0
Held for Sale [Member] | RSO [Member] | B Notes [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and receivables	0	0
Held for Sale [Member] | RSO [Member] | Mezzanine Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and receivables	0	0
Held for Sale [Member] | RSO [Member] | Bank Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and receivables	282	2,377
Held for Sale [Member] | RSO [Member] | Middle-market Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and receivables	$ 0	$ 4,473