Revenue and Accounts Receivable - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,627,461	$ 2,402,596	$ 2,036,524
Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	2,611,476	2,387,439	2,031,266
Rental revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 15,985	$ 15,157	$ 5,258
Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	100.00%	100.00%	100.00%
Medicaid | Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,022,460	$ 900,249	$ 802,952
Medicaid | Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	39.20%	37.70%	39.50%
Medicare | Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 727,103	$ 727,374	$ 499,353
Medicare | Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	27.80%	30.50%	24.60%
Medicaid — skilled | Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 172,770	$ 149,846	$ 132,889
Medicaid — skilled | Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	6.60%	6.30%	6.50%
Total Medicaid and Medicare | Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,922,333	$ 1,777,469	$ 1,435,194
Total Medicaid and Medicare | Customer Concentration Risk | Revenue Benchmark
Disaggregation of Revenue [Line Items]
Concentration risk	73.60%	74.50%	70.60%
Total Medicaid and Medicare | Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	73.60%	74.50%	70.60%
Managed care | Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 456,728	$ 367,095	$ 351,054
Managed care | Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	17.50%	15.40%	17.30%
Private and other | Service revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 232,415	$ 242,875	$ 245,018
Private and other | Customer Concentration Risk | Revenue Benchmark | Service revenue
Disaggregation of Revenue [Line Items]
Concentration risk	8.90%	10.10%	12.10%