NATURE OF OPERATIONS, CONSOLIDATION AND PRESENTATION OF FINANCIAL STATEMENTS - Narrative (Details) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2021 USD ($) state numberOfJointVentures care_center	Jun. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) state numberOfJointVentures care_center	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Number of states with facilities | state	38				38
Minimum ownership percentage for controlling interest (percent)	50.00%				50.00%
Maximum ownership percentage for equity method investment (percent)	50.00%				50.00%
Equity method investment, aggregate cost	$ 48,300				$ 48,300		$ 14,200
Proceeds from sale of equity method investment					0	$ 17,876
Gain (loss) on equity method investments	$ 0		$ 0		$ 31,092	$ (2,980)
Number of Consolidated Entities Classified as Variable Interest Entities | numberOfJointVentures	7				7
Cash and cash equivalents	$ 124,458				$ 124,458		81,808
Patient accounts receivable	274,570				274,570		255,145
Other current assets	14,024				14,024		13,265
Total current assets	432,882				432,882		361,984
Property and equipment	20,381				20,381		23,719
Total assets	1,937,645				1,937,645		1,567,198
Payroll and employee benefits	155,123				155,123		146,929
Accrued expenses	154,264				154,264		166,192
Current portion of long-term obligations	13,225				13,225		10,496
Total current liabilities	454,349				454,349		456,337
Other long-term obligations	31,991				31,991		33,622
Total liabilities	988,844				988,844		$ 756,457
Variable Interest Entity, Primary Beneficiary
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Cash and cash equivalents	3,700				3,700
Patient accounts receivable	2,500				2,500
Other current assets	100				100
Total current assets	6,300				6,300
Property and equipment	100				100
Total assets	6,400				6,400
Payroll and employee benefits	300				300
Accrued expenses	3,300				3,300
Current portion of long-term obligations	800				800
Total current liabilities	4,400				4,400
Other long-term obligations	100				100
Total liabilities	$ 4,500				$ 4,500
Heritage Healthcare Innovation Fund, LP [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Proceeds from sale of equity method investment				$ 17,900
Gain (loss) on equity method investments				$ 3,000
Medalogix [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Gain (loss) on equity method investments		$ 31,100
Home Health [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Number of owned and operated care centers | care_center	328				328
Hospice [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Number of owned and operated care centers | care_center	177				177
Personal Care [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Number of owned and operated care centers | care_center	14				14
High Acuity Care
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Number of Joint Ventures | numberOfJointVentures	8				8
Revenue from Contract with Customer [Member] | Product Concentration Risk | Medicare Revenue [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Percent of net services revenue	75.00%		76.00%		75.00%	75.00%