Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 6,664,058	$ 6,333,538	$ 6,204,515
Total patient services revenue
Disaggregation of Revenue [Line Items]
Total revenue	6,172,419	5,870,561	5,782,800
Medicare
Disaggregation of Revenue [Line Items]
Total revenue	1,486,076	1,448,546	1,418,970
Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	4,686,343	4,422,015	4,363,830
Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	491,639	462,977	421,715
Operating Segments | Critical Illness Recovery Hospital
Disaggregation of Revenue [Line Items]
Total revenue	2,299,773	2,234,132	2,246,772
Operating Segments | Critical Illness Recovery Hospital | Total patient services revenue
Disaggregation of Revenue [Line Items]
Total revenue	2,295,959	2,224,975	2,234,801
Operating Segments | Critical Illness Recovery Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	840,187	848,706	833,387
Operating Segments | Critical Illness Recovery Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	1,455,772	1,376,269	1,401,414
Operating Segments | Critical Illness Recovery Hospital | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	3,814	9,157	11,971
Operating Segments | Rehabilitation Hospital
Disaggregation of Revenue [Line Items]
Total revenue	979,585	916,763	849,340
Operating Segments | Rehabilitation Hospital | Total patient services revenue
Disaggregation of Revenue [Line Items]
Total revenue	930,915	872,206	807,249
Operating Segments | Rehabilitation Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	462,476	423,739	412,440
Operating Segments | Rehabilitation Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	468,439	448,467	394,809
Operating Segments | Rehabilitation Hospital | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	48,670	44,557	42,091
Operating Segments | Outpatient Rehabilitation
Disaggregation of Revenue [Line Items]
Total revenue	1,188,914	1,125,282	1,084,361
Operating Segments | Outpatient Rehabilitation | Total patient services revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,113,470	1,054,231	1,015,867
Operating Segments | Outpatient Rehabilitation | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	182,346	175,252	172,064
Operating Segments | Outpatient Rehabilitation | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	931,124	878,979	843,803
Operating Segments | Outpatient Rehabilitation | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	75,444	71,051	68,494
Operating Segments | Concentra
Disaggregation of Revenue [Line Items]
Total revenue	1,838,081	1,724,359	1,732,041
Operating Segments | Concentra | Total patient services revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,832,075	1,719,149	1,724,883
Operating Segments | Concentra | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	1,067	849	1,079
Operating Segments | Concentra | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	1,831,008	1,718,300	1,723,804
Operating Segments | Concentra | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	6,006	5,210	7,158
Corporate, non-Segment
Disaggregation of Revenue [Line Items]
Total revenue	357,705	333,002	292,001
Corporate, non-Segment | Total patient services revenue
Disaggregation of Revenue [Line Items]
Total revenue	0	0	0
Corporate, non-Segment | Medicare
Disaggregation of Revenue [Line Items]
Total revenue	0	0	0
Corporate, non-Segment | Non-Medicare
Disaggregation of Revenue [Line Items]
Total revenue	0	0	0
Corporate, non-Segment | Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 357,705	$ 333,002	$ 292,001