SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) quote	Jan. 01, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets	$ (6,624,875)		$ (51,762,731)	$ (55,186,630)
Total liabilities	(4,631,192)		(11,781,512)
Non-controlling redeemable interests in consolidated funds	(249,257)		(38,173,125)	(42,213,440)	$ (41,681,155)
Total unitholders’ capital	(1,744,426)		(1,808,094)	$ (1,888,052)	$ (1,840,130)
Debt issuance costs	$ 4,042		3,646
Variable Interest Entity [Line Items]
Number of broker quotes | quote	1
Accounting Standards Update 2015-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets		$ 45,700,000
Total liabilities		7,600,000
Non-controlling redeemable interests in consolidated funds		38,000,000
Total unitholders’ capital		90,600
Accounting Standards Update 2014-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total unitholders’ capital		$ 32,100
Long-term Debt | Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs			3,600
Other Assets | Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs			(3,600)
Minimum
Variable Interest Entity [Line Items]
Withdrawal period	1 month
Number of broker quotes | quote	1
Minimum | Contractual Rights to Earn Future Fee Income
Variable Interest Entity [Line Items]
Estimated useful lives in years	3 years
Maximum
Variable Interest Entity [Line Items]
Withdrawal period	3 years
Number of broker quotes | quote	2
Maximum | Contractual Rights to Earn Future Fee Income
Variable Interest Entity [Line Items]
Estimated useful lives in years	7 years
Consolidated Funds | Long-term Debt | Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs			44,700
Consolidated Funds | Other Assets | Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs			$ (44,700)