Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 91,860	$ 66,262	$ 177,117	$ 122,188
Other comprehensive income (loss), net of tax:
Gain on interest rate cap contract	17,527	11,833	14,831	51,647
Reclassification adjustment for losses (gains) included in net income	(15,134)	(6)	(28,386)	33
Net change, net of tax benefit (expense) of $(3,942), $(777), $(17,227), and $4,398	2,393	11,827	(13,555)	51,680
Comprehensive income	94,253	78,089	163,562	173,868
Less: Comprehensive income attributable to non-controlling interests	13,623	11,055	28,075	17,864
Comprehensive income attributable to Select Medical Holdings Corporation	$ 80,630	$ 67,034	$ 135,487	$ 156,004