Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,674,528	$ 1,584,741	$ 3,339,508	$ 3,184,288
Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	1,551,637	1,470,193	3,096,932	2,958,569
Medicare
Disaggregation of Revenue [Line Items]
Total revenue	368,090	363,338	753,572	727,427
Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	1,183,547	1,106,855	2,343,360	2,231,142
Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	122,891	114,548	242,576	225,719
Operating Segments | Critical Illness Recovery Hospital
Disaggregation of Revenue [Line Items]
Total revenue	575,091	545,908	1,169,017	1,147,663
Operating Segments | Critical Illness Recovery Hospital | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	574,241	542,798	1,166,929	1,142,771
Operating Segments | Critical Illness Recovery Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	207,743	213,680	437,126	432,667
Operating Segments | Critical Illness Recovery Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	366,498	329,118	729,803	710,104
Operating Segments | Critical Illness Recovery Hospital | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	850	3,110	2,088	4,892
Operating Segments | Rehabilitation Hospital
Disaggregation of Revenue [Line Items]
Total revenue	240,856	228,887	472,318	449,521
Operating Segments | Rehabilitation Hospital | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	228,886	218,031	448,866	428,194
Operating Segments | Rehabilitation Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	113,450	105,030	223,505	208,051
Operating Segments | Rehabilitation Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	115,436	113,001	225,361	220,143
Operating Segments | Rehabilitation Hospital | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	11,970	10,856	23,452	21,327
Operating Segments | Outpatient Rehabilitation
Disaggregation of Revenue [Line Items]
Total revenue	302,972	287,258	598,875	559,198
Operating Segments | Outpatient Rehabilitation | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	282,893	269,390	560,679	525,407
Operating Segments | Outpatient Rehabilitation | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	46,647	44,433	92,448	86,337
Operating Segments | Outpatient Rehabilitation | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	236,246	224,957	468,231	439,070
Operating Segments | Outpatient Rehabilitation | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	20,079	17,868	38,196	33,791
Operating Segments | Concentra
Disaggregation of Revenue [Line Items]
Total revenue	467,079	441,357	923,377	864,780
Operating Segments | Concentra | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	465,617	439,974	920,458	862,197
Operating Segments | Concentra | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	250	195	493	372
Operating Segments | Concentra | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	465,367	439,779	919,965	861,825
Operating Segments | Concentra | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,462	1,383	2,919	2,583
Other
Disaggregation of Revenue [Line Items]
Total revenue	88,530	81,331	175,921	163,126
Other | Total patient services revenues
Disaggregation of Revenue [Line Items]
Total revenue	0	0	0	0
Other | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	0	0	0	0
Other | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	0	0	0	0
Other | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 88,530	$ 81,331	$ 175,921	$ 163,126