GOODWILL AND OTHER INTANGIBLE ASSETS - Carrying Amount and Accumulated Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Total gross intangible assets	$ 554,527		$ 554,527		$ 549,066
Total accumulated amortization	(210,533)		(210,533)		(184,951)
Total intangible assets, net	343,994		343,994		364,115
Amortization expense for intangible assets	8,600	$ 8,400	25,600	$ 24,600
Referral sources
Finite-Lived Intangible Assets [Line Items]
Total gross intangible assets	514,388		514,388		509,646
Total accumulated amortization	(191,262)		(191,262)		(167,902)
Trademarks/names
Finite-Lived Intangible Assets [Line Items]
Total gross intangible assets	39,136		39,136		38,508
Total accumulated amortization	(18,973)		(18,973)		(16,901)
Other amortizable intangible assets
Finite-Lived Intangible Assets [Line Items]
Total gross intangible assets	1,003		1,003		912
Total accumulated amortization	$ (298)		$ (298)		$ (148)