FAIR VALUE OF FINANCIAL INSTRUMENTS (Details 3) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reconciliation of liabilities measured on Level 3 basis
Transfers from Level 1 into Level 2	$ 0	$ 0
Transfers from Level 2 into Level 1	0	0
Collateralized Loan Obligation Secured Notes
Reconciliation of liabilities measured on Level 3 basis
Balance at the beginning of the period		5,501,099,000
Included in earnings		0
Transfers into Level 3		0
Transfers out of level 3		(5,501,099,000)
Purchases		0
Sales		0
Settlements		0
Balance at the end of the period		0
Change in unrealized gains or losses for the period included in earnings for liabilities held at the end of the reporting period		0
Corporate Debt Securities
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	194,986,000	317,034,000
Included in earnings	(44,882,000)	(3,996,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	$ 0	0
Sales		(4,213,000)
Settlements	$ (36,000)	(914,000)
Balance at the end of the period	150,068,000	307,911,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	(44,882,000)	(9,354,000)
Residential Mortgage- Backed Securities
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	49,621,000	55,184,000
Included in earnings	332,000	1,776,000
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Settlements	(2,239,000)	(3,025,000)
Balance at the end of the period	47,714,000	53,935,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	329,000	153,000
Corporate loans, at estimated fair value
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	298,734,000	347,077,000
Included in earnings	(6,827,000)	(55,770,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	2,306,000	1,308,000
Sales	0	(25,511,000)
Settlements	2,769,000	69,082,000
Balance at the end of the period	296,982,000	336,186,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	(6,827,000)	(55,026,000)
Equity Investments, at Estimated Fair Value
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	146,648,000	81,719,000
Included in earnings	(8,085,000)	(23,327,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Settlements	0	44,927,000
Balance at the end of the period	138,563,000	103,319,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	(8,085,000)	(22,961,000)
Interests in Joint Ventures and Partnerships
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	888,408,000	718,772,000
Included in earnings	(80,695,000)	(32,362,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	14,067,000	35,537,000
Sales	0	0
Settlements	(73,451,000)	(2,657,000)
Balance at the end of the period	748,329,000	719,290,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	(80,695,000)	(32,362,000)
Foreign Exchange Options, Net
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	2,887,000
Included in earnings	(1,046,000)
Transfers into Level 3	0
Transfers out of Level 3	0
Purchases	0
Sales	0
Settlements	0
Balance at the end of the period	1,841,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	(1,046,000)
Common stock warrants
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period		0
Included in earnings		(1,891,000)
Transfers into Level 3		0
Transfers out of Level 3		0
Purchases		0
Sales		0
Settlements		2,412,000
Balance at the end of the period		521,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period		(1,891,000)
Options
Reconciliation of assets measured on Level 3 basis
Balance at the beginning of the period	95,000	5,212,000
Included in earnings	403,000	(903,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Settlements	0	0
Balance at the end of the period	498,000	4,309,000
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the reporting period	$ 403,000	$ (903,000)