Income per Common Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Numerator:
Net income attributable to Select Medical Holdings Corporation	$ 43,172	$ 11,719	$ 84,714	$ 45,391
Less: Earnings allocated to unvested restricted stockholders	707	125	1,338	486
Net income available to common stockholders	$ 42,465	$ 11,594	$ 83,376	$ 44,905
Denominator:
Weighted average shares - basic	138,456	152,603	139,941	152,720
Effect of dilutive securities: Stock options (in shares)	229	278	221	231
Weighted average shares - diluted	138,685	152,881	140,162	152,951
Income per common share
Basic income per common share (in dollars per share)	$ 0.31	$ 0.08	$ 0.60	$ 0.29
Diluted income per common share (in dollars per share)	$ 0.31	$ 0.08	$ 0.59	$ 0.29
Anti-dilutive securities excluded from computation of earnings per share
Stock options (in shares)	1,684	1,691	1,699	2,400