SEGMENT REPORTING - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total Segment Revenues	$ 1,129,666	$ 749,652	$ 2,573,892	$ 2,533,207
Deduct: Capital Allocation-Based Income (GAAP)	638,163	394,234	1,274,149	1,416,825
Add: Segment Realized Carried Interest	543,750	337,459	1,097,673	1,224,235
Add: Segment Realized Investment Income (Loss)	833,288	177,953	2,748,604	1,289,638
Segment Reconciling Items
Segment Reporting Information [Line Items]
Add: Management Fees - Consolidated Funds and Other	104,356	53,454	270,383	155,418
Deduct: Fee Credits - Consolidated Funds	8,283	106	41,178	3,752
Deduct: Capital Allocation-Based Income (GAAP)	638,163
Add: Segment Realized Carried Interest	414,609	419,438	959,253	890,310
Add: Segment Realized Investment Income (Loss)	242,743	146,610	491,903	357,959
Deduct: Revenue Earned by Other Consolidated Entities	27,749	21,470	84,342	76,135
Deduct: Expense Reimbursements	38,212	27,506	108,999	87,131
Reportable segments
Segment Reporting Information [Line Items]
Total Segment Revenues	1,178,967	925,838	2,786,763	2,353,051
Add: Segment Realized Carried Interest	414,609	419,438	959,253	890,310
Add: Segment Realized Investment Income (Loss)	$ 242,743	$ 146,610	$ 491,903	$ 357,959