VARIABLE INTEREST ENTITIES FINANCING RECEIVABLES (Allowance for Loan Losses and Recorded Investments in Loans) (Details) RSO (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Loans charged-off	$ (32)	$ (1)
Recoveries	0	1
Allowance for losses, ending balance:
Individually evaluated for impairment	17,360	37,441
Collectively evaluated for impairment	0	10
Loans, ending balance:
Individually evaluated for impairment	44,146		47,293
Collectively evaluated for impairment	118		88
RSO [Member]
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Allowance for losses at beginning of period	4,613	13,807	13,807
Provision (recovery) for loan losses	3,990		1,804
Loans charged-off	(1,328)		(10,998)
Recoveries	110
Allowance for losses at end of period	7,385		4,613
Allowance for losses, ending balance:
Individually evaluated for impairment	4,800		570
Collectively evaluated for impairment	2,585		4,043
Loans acquired with deteriorated credit quality	0		0
Loans, ending balance:
Individually evaluated for impairment	462,417		418,920
Collectively evaluated for impairment	1,580,339		1,513,232
Loans acquired with deteriorated credit quality	0		0
RSO [Member] | Commercial Real Estate Loans [Member]
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Allowance for losses at beginning of period	4,043	10,416	10,416
Provision (recovery) for loan losses	0		(3,758)
Loans charged-off	0		(2,615)
Recoveries	0
Allowance for losses at end of period	4,043		4,043
Allowance for losses, ending balance:
Individually evaluated for impairment	2,202		0
Collectively evaluated for impairment	1,841		4,043
Loans acquired with deteriorated credit quality	0		0
Loans, ending balance:
Individually evaluated for impairment	166,180		166,180
Collectively evaluated for impairment	1,279,704		1,180,850
Loans acquired with deteriorated credit quality	0		0
RSO [Member] | Bank Loans [Member]
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Allowance for losses at beginning of period	570	3,391	3,391
Provision (recovery) for loan losses	1,415		4,173
Loans charged-off	(1,265)		(6,994)
Recoveries	0
Allowance for losses at end of period	720		570
Allowance for losses, ending balance:
Individually evaluated for impairment	86		570
Collectively evaluated for impairment	634		0
Loans acquired with deteriorated credit quality	0		0
Loans, ending balance:
Individually evaluated for impairment	215		1,350
Collectively evaluated for impairment	297,994		329,580
Loans acquired with deteriorated credit quality	0		0
RSO [Member] | Middle-market Loans [Member]
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Allowance for losses at beginning of period	0	0	0
Provision (recovery) for loan losses	2,566		92
Loans charged-off	(54)		(92)
Recoveries	0
Allowance for losses at end of period	2,512		0
Allowance for losses, ending balance:
Individually evaluated for impairment	2,512		0
Collectively evaluated for impairment	0		0
Loans acquired with deteriorated credit quality	0		0
Loans, ending balance:
Individually evaluated for impairment	294,793		250,113
Collectively evaluated for impairment	0		0
Loans acquired with deteriorated credit quality	0		0
RSO [Member] | Residential Mortgage Loans [Member]
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Allowance for losses at beginning of period	0	0	0
Provision (recovery) for loan losses	197		0
Loans charged-off	(197)		0
Recoveries	110
Allowance for losses at end of period	110		0
Allowance for losses, ending balance:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	110		0
Loans acquired with deteriorated credit quality	0		0
Loans, ending balance:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	2,641		2,802
Loans acquired with deteriorated credit quality	0		0
RSO [Member] | Loans Receivable - Related Party [Member]
Activity in the allowance for credit losses of financing receivables [Roll Forward]
Allowance for losses at beginning of period	0	0	0
Provision (recovery) for loan losses	(188)		1,297
Loans charged-off	188		(1,297)
Recoveries	0
Allowance for losses at end of period	0		0
Allowance for losses, ending balance:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	0		0
Loans acquired with deteriorated credit quality	0		0
Loans, ending balance:
Individually evaluated for impairment	1,229		1,277
Collectively evaluated for impairment	0		0
Loans acquired with deteriorated credit quality	$ 0		$ 0