Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 6,664,058	$ 6,333,538	$ 6,204,515
Costs and expenses:
Cost of services, exclusive of depreciation and amortization	5,732,017	5,600,161	5,285,149
General and administrative	170,193	153,035	146,975
Depreciation and amortization	208,742	205,825	202,645
Total costs and expenses	6,110,952	5,959,021	5,634,769
Other operating income	1,768	28,766	144,028
Income from operations	554,874	403,283	713,774
Other income and expense:
Loss on early retirement of debt	(14,692)	0	0
Equity in earnings of unconsolidated subsidiaries	40,813	26,407	44,428
Gain on sale of businesses	0	0	2,155
Interest income	0	0	5,350
Interest expense	(198,639)	(169,111)	(135,985)
Income before income taxes	382,356	260,579	629,722
Income tax expense	82,625	62,553	129,773
Net income	299,731	198,026	499,949
Less: Net income attributable to non-controlling interests	56,240	39,032	97,724
Net income attributable to Select Medical Holdings Corporation	$ 243,491	$ 158,994	$ 402,225
Earnings per common share (Note 19):
Basic (in dollars per share)	$ 1.91	$ 1.23	$ 2.98
Diluted (in dollars per share)	$ 1.91	$ 1.23	$ 2.98