Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 299,731	$ 198,026	$ 499,949
Other comprehensive income (loss), net of tax:
Gain on interest rate cap contract	15,783	90,730	14,270
Reclassification adjustment for (gains) losses included in net income	(61,478)	(14,410)	39
Net change, net of tax expense of $(4,799), $(24,658) and $(15,202)	(45,695)	76,320	14,309
Comprehensive income	254,036	274,346	514,258
Less: Comprehensive income attributable to non-controlling interests	56,240	39,032	97,724
Comprehensive income attributable to Select Medical Holdings Corporation	$ 197,796	$ 235,314	$ 416,534