RELATED-PARTY TRANSACTIONS (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2015 agreement
Related Party Transaction [Line Items]
Number of agreements | agreement				2
Selling, general and administrative expenses	$ 525,707,000	$ 500,199,000	$ 459,628,000
Sale Of Notes Receivable
Related Party Transaction [Line Items]
Sale of management notes receivable			1,300,000
Madison Dearborn Partners VI-B, L.P. | Option Care Acquisition
Related Party Transaction [Line Items]
Due to joint ventures	300,000
Management
Related Party Transaction [Line Items]
Selling, general and administrative expenses			1,500,000
Notes receivable	0	0	0
Management | Sale Of Notes Receivable
Related Party Transaction [Line Items]
Sale of management notes receivable			1,100,000
Accrued interest expense			200,000
HC Group Holdings I, LLC | Loans Funded For Membership Unit Purchase
Related Party Transaction [Line Items]
Shareholder redemptions	0	0	2,400,000
Cash distributions			2,000,000
Notes redeemed			400,000
Joint Venture
Related Party Transaction [Line Items]
Due to joint ventures	1,400,000		4,300,000
Management fee income	$ 3,500,000	2,900,000	$ 2,500,000
Due from joint ventures		$ 2,400,000