Intangible Assets - Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill
Balance at the beginning of the year	$ 3,484,200	$ 3,448,912
Acquisition of businesses	28,970	22,037
Measurement period adjustment		13,251
Balance at the end of the year	3,513,170	3,484,200
Critical Illness Recovery Hospital
Goodwill
Balance at the beginning of the year	1,151,196	1,131,440
Acquisition of businesses	6,606	6,505
Measurement period adjustment		13,251
Balance at the end of the year	1,157,802	1,151,196
Rehabilitation Hospital
Goodwill
Balance at the beginning of the year	442,155	442,155
Acquisition of businesses	16,185	0
Measurement period adjustment		0
Balance at the end of the year	458,340	442,155
Outpatient Rehabilitation
Goodwill
Balance at the beginning of the year	664,978	654,125
Acquisition of businesses	2,305	10,853
Measurement period adjustment		0
Balance at the end of the year	667,283	664,978
Concentra
Goodwill
Balance at the beginning of the year	1,225,871	1,221,192
Acquisition of businesses	3,874	4,679
Measurement period adjustment		0
Balance at the end of the year	$ 1,229,745	$ 1,225,871