DERIVATIVE FINANCIAL INSTRUMENTS (Details 2) (Net realized (loss) on investments, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
AM LLC and AIH LLC
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	$ (1,134)	$ (1,165)
Total net change in unrealized appreciation (depreciation) on investments	(67)	4,673
AM LLC and AIH LLC | Options | Purchased
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments	(61)	247
AM LLC and AIH LLC | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(341)	(302)
Total net change in unrealized appreciation (depreciation) on investments	57	223
AM LLC and AIH LLC | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(793)	(863)
Total net change in unrealized appreciation (depreciation) on investments	(63)	4,203
AM LLC and AIH LLC | Interest rate contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(341)	(302)
Total net change in unrealized appreciation (depreciation) on investments	57	223
AM LLC and AIH LLC | Interest rate contracts | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(341)	(302)
Total net change in unrealized appreciation (depreciation) on investments	57	223
AM LLC and AIH LLC | Foreign exchange contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(793)	(863)
Total net change in unrealized appreciation (depreciation) on investments	(124)	4,450
AM LLC and AIH LLC | Foreign exchange contracts | Options | Purchased
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments	(61)	247
AM LLC and AIH LLC | Foreign exchange contracts | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(793)	(863)
Total net change in unrealized appreciation (depreciation) on investments	(63)	4,203
Consolidated Funds
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(24,240)	(3,074)
Total net change in unrealized appreciation (depreciation) on investments	7,804	34,481
Consolidated Funds | Options | Purchased
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(2,292)	(1,883)
Total net change in unrealized appreciation (depreciation) on investments	(1,668)	(30)
Consolidated Funds | Options | Written
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	1,853	337
Total net change in unrealized appreciation (depreciation) on investments	(1,214)	(35)
Consolidated Funds | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(7,174)	(2,522)
Total net change in unrealized appreciation (depreciation) on investments	(472)	4,589
Consolidated Funds | Interest rate caps/floor
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments		1,526
Total net change in unrealized appreciation (depreciation) on investments	(4)	(1,713)
Consolidated Funds | Warrants
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	1,261	33
Total net change in unrealized appreciation (depreciation) on investments	(7,180)	2,939
Consolidated Funds | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(17,888)	(565)
Total net change in unrealized appreciation (depreciation) on investments	18,342	28,731
Consolidated Funds | Interest rate contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(514)	(2,755)
Total net change in unrealized appreciation (depreciation) on investments	(368)	1,783
Consolidated Funds | Interest rate contracts | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(514)	(2,755)
Total net change in unrealized appreciation (depreciation) on investments	(342)	1,785
Consolidated Funds | Interest rate contracts | Interest rate caps/floor
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments	(4)	(2)
Consolidated Funds | Interest rate contracts | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments	(22)
Consolidated Funds | Credit contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(10,206)
Total net change in unrealized appreciation (depreciation) on investments	3,476	1,403
Consolidated Funds | Credit contracts | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(10,206)
Total net change in unrealized appreciation (depreciation) on investments	3,476	(734)
Consolidated Funds | Credit contracts | Warrants
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments		2,137
Consolidated Funds | Equity contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(758)	(1,532)
Total net change in unrealized appreciation (depreciation) on investments	(5,850)	30,482
Consolidated Funds | Equity contracts | Options | Purchased
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(2,019)	(1,565)
Total net change in unrealized appreciation (depreciation) on investments	108	140
Consolidated Funds | Equity contracts | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments		762
Consolidated Funds | Equity contracts | Warrants
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	1,261	33
Total net change in unrealized appreciation (depreciation) on investments	(7,180)	802
Consolidated Funds | Equity contracts | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments	1,222	28,778
Consolidated Funds | Foreign exchange contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(16,308)	1,213
Total net change in unrealized appreciation (depreciation) on investments	14,250	(758)
Consolidated Funds | Foreign exchange contracts | Options | Purchased
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(273)	(318)
Total net change in unrealized appreciation (depreciation) on investments	(1,663)	(170)
Consolidated Funds | Foreign exchange contracts | Options | Written
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	1,853	337
Total net change in unrealized appreciation (depreciation) on investments	(1,214)	(35)
Consolidated Funds | Foreign exchange contracts | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments		233
Total net change in unrealized appreciation (depreciation) on investments	(15)	971
Consolidated Funds | Foreign exchange contracts | Interest rate caps/floor
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments		1,526
Total net change in unrealized appreciation (depreciation) on investments		(1,711)
Consolidated Funds | Foreign exchange contracts | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	(17,888)	(565)
Total net change in unrealized appreciation (depreciation) on investments	17,142	187
Consolidated Funds | Other financial instruments
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	3,546
Total net change in unrealized appreciation (depreciation) on investments	(3,704)	1,571
Consolidated Funds | Other financial instruments | Options | Purchased
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments	(113)
Consolidated Funds | Other financial instruments | Swaps
DERIVATIVE FINANCIAL INSTRUMENTS
Total net realized gain (loss) on investments	3,546
Total net change in unrealized appreciation (depreciation) on investments	(3,591)	1,805
Consolidated Funds | Other financial instruments | Foreign currency forward contracts
DERIVATIVE FINANCIAL INSTRUMENTS
Total net change in unrealized appreciation (depreciation) on investments		$ (234)