Condensed Consolidated Statements of Changes in Equity and Income - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Total	Select Medical Corporation	Common Stock	Common Stock Select Medical Corporation	Capital in Excess of Par	Capital in Excess of Par Select Medical Corporation	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Select Medical Corporation	Total Stockholders’ Equity	Total Stockholders’ Equity Select Medical Corporation	Non-controlling Interests	Non-controlling Interests Select Medical Corporation
Balance at Dec. 31, 2017	$ 640,818	$ 640,818
Redeemable Non-controlling Interests
Net income attributable to non-controlling interests	5,743	5,743
Exchange of interests	163,659	163,659
Distributions to non-controlling interests	(203,972)	(203,972)
Redemption adjustment on non-controlling interests	1,051	1,051
Other	175	175
Balance at Mar. 31, 2018	$ 607,474	$ 607,474
Balance (in shares) at Dec. 31, 2017	134,114,715	100	134,115,000	0
Balance at Dec. 31, 2017	$ 932,604	$ 932,604	$ 134	$ 0	$ 463,499	$ 947,370	$ 359,735	$ (124,002)	$ 823,368	$ 823,368	$ 109,236	$ 109,236
Increase (Decrease) in Stockholders' Equity
Net income	33,739	33,739					33,739	33,739	33,739	33,739
Net income attributable to non-controlling interests	4,500	4,500									4,500	4,500
Issuance of restricted stock (in shares)			4,000
Issuance of restricted stock	0		$ 0		0
Forfeitures of unvested restricted stock (in shares)			(88,000)
Forfeitures of unvested restricted stock	0		$ 0		0
Vesting of restricted stock	4,717				4,717				4,717
Repurchase of common shares (in shares)			(7,000)
Repurchase of common shares	(122)		$ 0		(69)		(53)		(122)
Exercise of stock options (in shares)			80,000
Exercise of stock options	738		$ 0		738				738
Additional investment by Holdings		738				738				738
Dividends declared and paid to Holdings		(122)						(122)		(122)
Contribution related to restricted stock award issuances by Holdings		4,717				4,717				4,717
Exchange of interests	74,341	74,341					74,341	74,341	74,341	74,341
Distributions to non-controlling interests	(84,327)	(84,327)					(83,233)	(83,233)	(83,233)	(83,233)	(1,094)	(1,094)
Redemption adjustment on non-controlling interests	(1,051)	(1,051)					(1,051)	(1,051)	(1,051)	(1,051)
Other	$ 138	$ 138					103	103	103	103	35	35
Balance (in shares) at Mar. 31, 2018	134,104,286	100	134,104,000	0
Balance at Mar. 31, 2018	$ 965,277	$ 965,277	$ 134	$ 0	$ 468,885	$ 952,825	$ 383,581	$ (100,225)	$ 852,600	$ 852,600	$ 112,677	$ 112,677