GOODWILL AND OTHER INTANGIBLE ASSETS - Intangible assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortizing acquired intangible assets
Gross Carry Amount	$ 2,673,831	$ 2,430,950
Accumulated Amortization	(1,036,015)	(849,231)
Net Book Value	1,637,816	1,581,719
Customer relationships
Amortizing acquired intangible assets
Gross Carry Amount	2,460,851	2,228,461
Accumulated Amortization	(962,690)	(787,016)
Net Book Value	1,498,161	1,441,445
Management contracts
Amortizing acquired intangible assets
Gross Carry Amount	199,761	191,578
Accumulated Amortization	(66,860)	(57,153)
Net Book Value	132,901	134,425
Other acquired intangibles
Amortizing acquired intangible assets
Gross Carry Amount	13,219	10,911
Accumulated Amortization	(6,465)	(5,062)
Net Book Value	$ 6,754	$ 5,849