VARIABLE INTEREST ENTITIES BORROWINGS (Schedule of Debt) (Details) RSO (RSO [Member], USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Outstanding Borrowings	$ 1,952,765,000	$ 1,734,901,000
Principal Outstanding	28,167,000	18,030,000
Unamortized Issuance Costs and Discounts	1,924,598,000	1,716,871,000
Long-term Debt, Weighted Average Interest Rate	2.46%	2.09%
Weighted Average Remaining Maturity	10 years 9 months	10 years 0 months
Value of Collateral	2,391,514,000	2,287,115,000
Interest Payable	5,437,000	2,123,000
RREF CDO 2006-1 Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	52,957,000	61,423,000
Principal Outstanding	0	0
Unamortized Issuance Costs and Discounts	52,957,000	61,423,000
Long-term Debt, Weighted Average Interest Rate	2.31%	2.12%
Weighted Average Remaining Maturity	31 years 5 months	31 years 7 months
Value of Collateral	130,727,000	139,242,000
RREF CDO 2007-1 Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	131,780,000	130,340,000
Principal Outstanding	63,000	133,000
Unamortized Issuance Costs and Discounts	131,717,000	130,207,000
Long-term Debt, Weighted Average Interest Rate	1.14%	1.19%
Weighted Average Remaining Maturity	31 years 6 months	31 years 9 months
Value of Collateral	258,175,000	271,423,000
RCC CRE Notes 2013 [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	182,040,000	226,840,000
Principal Outstanding	2,493,000	2,683,000
Unamortized Issuance Costs and Discounts	179,547,000	224,157,000
Long-term Debt, Weighted Average Interest Rate	2.28%	2.11%
Weighted Average Remaining Maturity	13 years 8 months	14 years 0 months
Value of Collateral	205,386,000	249,983,000
RCC CRE Notes 2014 [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	235,344,000	235,344,000
Principal Outstanding	3,682,000	3,687,000
Unamortized Issuance Costs and Discounts	231,662,000	231,657,000
Long-term Debt, Weighted Average Interest Rate	1.47%	1.45%
Weighted Average Remaining Maturity	17 years 1 month	17 years 4 months
Value of Collateral	349,063,000	346,585,000
RCC CRE Notes 2015 [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	282,127,000
Principal Outstanding	4,116,000
Unamortized Issuance Costs and Discounts	278,011,000
Long-term Debt, Weighted Average Interest Rate	2.07%
Weighted Average Remaining Maturity	17 years 0 months
Value of Collateral	339,654,000
Apidos CDO III Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	67,028,000	74,646,000
Principal Outstanding	0	0
Unamortized Issuance Costs and Discounts	67,028,000	74,646,000
Long-term Debt, Weighted Average Interest Rate	1.28%	1.18%
Weighted Average Remaining Maturity	5 years 6 months	5 years 8 months
Value of Collateral	78,957,000	85,553,000
Apidos Cinco CDO Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	229,716,000	255,664,000
Principal Outstanding	72,000	201,000
Unamortized Issuance Costs and Discounts	229,644,000	255,463,000
Long-term Debt, Weighted Average Interest Rate	0.87%	0.81%
Weighted Average Remaining Maturity	5 years 1 month	5 years 5 months
Value of Collateral	252,826,000	272,512,000
Moselle CLO S.A. Securitized Borrowings [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	120,000	5,619,000
Principal Outstanding	0	0
Unamortized Issuance Costs and Discounts	120,000	5,619,000
Long-term Debt, Weighted Average Interest Rate		1.49%
Weighted Average Remaining Maturity		5 years 0 months
Value of Collateral	537,000	0
Moselle CLO S.A. Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings		63,321,000
Principal Outstanding		0
Unamortized Issuance Costs and Discounts		63,321,000
Long-term Debt, Weighted Average Interest Rate		1.49%
Weighted Average Remaining Maturity		5 years 0 months
Value of Collateral		93,576,000
Interest Payable		20,000
CDO notes		63,300,000
Unsecured Junior Subordinated Debentures [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	51,548,000	51,548,000
Principal Outstanding	292,000	343,000
Unamortized Issuance Costs and Discounts	51,256,000	51,205,000
Long-term Debt, Weighted Average Interest Rate	4.21%	4.19%
Weighted Average Remaining Maturity	21 years 7 months	21 years 10 months
Value of Collateral	0	0
Six Percent Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	115,000,000	115,000,000
Principal Outstanding	6,182,000	6,626,000
Unamortized Issuance Costs and Discounts	108,818,000	108,374,000
Long-term Debt, Weighted Average Interest Rate	6.00%	6.00%
Weighted Average Remaining Maturity	3 years 8 months	3 years 11 months
Value of Collateral	0	0
Eight Percent Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	100,000,000
Principal Outstanding	7,052,000
Unamortized Issuance Costs and Discounts	92,948,000
Long-term Debt, Weighted Average Interest Rate	8.00%
Weighted Average Remaining Maturity	4 years 9 months
Value of Collateral	0
CRE - Term Repurchase Facility [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	93,734,000	207,640,000
Principal Outstanding	1,583,000	1,958,000
Unamortized Issuance Costs and Discounts	92,151,000	205,682,000
Long-term Debt, Weighted Average Interest Rate	2.21%	2.43%
Weighted Average Remaining Maturity	18 days	20 days
Value of Collateral	135,951,000	297,571,000
Interest Payable	75,000	198,000
Repurchase Agreements Debt [Member]
Debt Instrument [Line Items]
Outstanding Borrowings		24,967,000
Principal Outstanding		0
Unamortized Issuance Costs and Discounts		24,967,000
Long-term Debt, Weighted Average Interest Rate		1.35%
Weighted Average Remaining Maturity		20 days
Value of Collateral		30,180,000
CMBS - Term Repurchase Facilities [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	29,391,000
Principal Outstanding	0
Unamortized Issuance Costs and Discounts	29,391,000
Long-term Debt, Weighted Average Interest Rate	1.37%
Weighted Average Remaining Maturity	18 days
Value of Collateral	35,977,000
Interest Payable	13,000	12,000
RMBS - Term Repurchase Facility [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	104,547,000	22,248,000
Principal Outstanding	125,000	36,000
Unamortized Issuance Costs and Discounts	104,422,000	22,212,000
Long-term Debt, Weighted Average Interest Rate	2.43%	1.16%
Weighted Average Remaining Maturity	25 days	1 day
Value of Collateral	121,472,000	27,885,000
Interest Payable	39,000	31,000
Residential Mortgage Financing Agreements [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	74,648,000
Principal Outstanding	0
Unamortized Issuance Costs and Discounts	74,648,000
Long-term Debt, Weighted Average Interest Rate	2.78%
Weighted Average Remaining Maturity	130 days
Value of Collateral	95,479,000
CMBS - Short Term Repurchase Agreements [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	67,785,000	44,225,000
Principal Outstanding	0	0
Unamortized Issuance Costs and Discounts	67,785,000	44,225,000
Long-term Debt, Weighted Average Interest Rate	1.63%	1.63%
Weighted Average Remaining Maturity	18 days	17 days
Value of Collateral	94,857,000	62,446,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding Borrowings	135,000,000	113,500,000
Principal Outstanding	2,507,000	2,363,000
Unamortized Issuance Costs and Discounts	132,493,000	111,137,000
Long-term Debt, Weighted Average Interest Rate	2.68%	2.66%
Weighted Average Remaining Maturity	2 years 6 months	2 years 8 months
Value of Collateral	292,453,000	262,687,000
Mortgages [Member]
Debt Instrument [Line Items]
Outstanding Borrowings		102,576,000
Principal Outstanding		0
Unamortized Issuance Costs and Discounts		102,576,000
Long-term Debt, Weighted Average Interest Rate		2.78%
Weighted Average Remaining Maturity		207 days
Value of Collateral		$ 147,472,000