BUSINESS SEGMENTS - Revenue by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 3,008,711	$ 2,611,476	$ 2,387,439
Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	100.00%	100.00%	100.00%
Total Medicaid and Medicare
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 2,216,194	$ 1,922,333	$ 1,777,469
Total Medicaid and Medicare \| Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	73.70%	73.60%	74.50%
Medicaid
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 1,183,156	$ 1,022,460	$ 900,249
Medicaid \| Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	39.30%	39.20%	37.70%
Medicare
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 832,160	$ 727,103	$ 727,374
Medicare \| Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	27.70%	27.80%	30.50%
Medicare
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 200,878	$ 172,770	$ 149,846
Medicare \| Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	6.70%	6.60%	6.30%
Managed care
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 525,710	$ 456,728	$ 367,095
Managed care \| Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	17.50%	17.50%	15.40%
Private and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 266,807	$ 232,415	$ 242,875
Private and other \| Revenue Benchmark \| Customer Concentration Risk
Segment Reporting, Revenue Reconciling Item [Line Items]
Concentration risk	8.80%	8.90%	10.10%
Operating Segments \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 2,906,215	$ 2,523,234	$ 2,288,182
Operating Segments \| Total Medicaid and Medicare \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	2,191,347	1,906,934	1,764,211
Operating Segments \| Medicaid \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	1,158,309	1,007,061	886,991
Operating Segments \| Medicare \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	832,160	727,103	727,374
Operating Segments \| Medicare \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	200,878	172,770	149,846
Operating Segments \| Managed care \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	525,710	456,728	367,095
Operating Segments \| Private and other \| Skilled Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	189,158	159,572	156,876
Other Service Revenue
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	102,496	88,242	99,257
Other Service Revenue \| Total Medicaid and Medicare
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	24,847	15,399	13,258
Other Service Revenue \| Medicaid
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	24,847	15,399	13,258
Other Service Revenue \| Medicare
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	0	0	0
Other Service Revenue \| Medicare
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	0	0	0
Other Service Revenue \| Managed care
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	0	0	0
Other Service Revenue \| Private and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Service revenue	$ 77,649	$ 72,843	$ 85,999