Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,599,547	$ 1,546,463
Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	1,488,376	1,449,003
Medicare
Disaggregation of Revenue [Line Items]
Total revenue	364,089	371,036
Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	1,124,287	1,077,967
Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	111,171	97,460
Operating Segments | Critical Illness Recovery Hospital
Disaggregation of Revenue [Line Items]
Total revenue	601,755	594,872
Operating Segments | Critical Illness Recovery Hospital | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	599,973	593,292
Operating Segments | Critical Illness Recovery Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	218,987	232,140
Operating Segments | Critical Illness Recovery Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	380,986	361,152
Operating Segments | Critical Illness Recovery Hospital | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,782	1,580
Operating Segments | Rehabilitation Hospital
Disaggregation of Revenue [Line Items]
Total revenue	220,634	207,804
Operating Segments | Rehabilitation Hospital | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	210,163	197,717
Operating Segments | Rehabilitation Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	103,021	102,375
Operating Segments | Rehabilitation Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	107,142	95,342
Operating Segments | Rehabilitation Hospital | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	10,471	10,087
Operating Segments | Outpatient Rehabilitation
Disaggregation of Revenue [Line Items]
Total revenue	271,940	251,961
Operating Segments | Outpatient Rehabilitation | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	256,017	237,110
Operating Segments | Outpatient Rehabilitation | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	41,904	36,291
Operating Segments | Outpatient Rehabilitation | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	214,113	200,819
Operating Segments | Outpatient Rehabilitation | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	15,923	14,851
Operating Segments | Concentra
Disaggregation of Revenue [Line Items]
Total revenue	423,423	422,840
Operating Segments | Concentra | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	422,223	420,884
Operating Segments | Concentra | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	177	230
Operating Segments | Concentra | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	422,046	420,654
Operating Segments | Concentra | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,200	1,956
Other
Disaggregation of Revenue [Line Items]
Total revenue	81,795	68,986
Other | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	0	0
Other | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	0	0
Other | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	0	0
Other | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 81,795	$ 68,986