GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 787,972
Acquisitions	213,328
Reallocation	0
Foreign currency translation	(2,856)
Goodwill, ending balance	998,444
Credit Group
Goodwill [Roll Forward]
Goodwill, beginning balance	32,196
Acquisitions	0
Reallocation	0
Foreign currency translation	0
Goodwill, ending balance	32,196
Private Equity Group
Goodwill [Roll Forward]
Goodwill, beginning balance	58,600
Acquisitions	0
Reallocation	(10,530)
Foreign currency translation	0
Goodwill, ending balance	48,070
Real Assets Group
Goodwill [Roll Forward]
Goodwill, beginning balance	53,339
Acquisitions	213,424
Reallocation	10,530
Foreign currency translation	0
Goodwill, ending balance	277,293
Secondary Solutions Group
Goodwill [Roll Forward]
Goodwill, beginning balance	417,738
Acquisitions	(96)
Reallocation	0
Foreign currency translation	(21)
Goodwill, ending balance	417,621
Strategic Initiatives
Goodwill [Roll Forward]
Goodwill, beginning balance	226,099
Acquisitions	0
Reallocation	0
Foreign currency translation	(2,835)
Goodwill, ending balance	$ 223,264