Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Critical Illness Recovery Hospital
Disaggregation of Revenue [Line Items]
Total net operating revenues	$ 420,108	$ 416,934	$ 1,327,236	$ 1,301,251
Critical Illness Recovery Hospital | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	416,730	412,988	1,316,668	1,292,658
Critical Illness Recovery Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	210,101	217,116	676,950	682,286
Critical Illness Recovery Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	206,629	195,872	639,718	610,372
Critical Illness Recovery Hospital | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	3,378	3,946	10,568	8,593
Rehabilitation Hospital
Disaggregation of Revenue [Line Items]
Total net operating revenues	176,885	157,499	525,428	453,702
Rehabilitation Hospital | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	135,886	117,281	406,070	335,551
Rehabilitation Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	71,564	64,227	217,459	183,820
Rehabilitation Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	64,322	53,054	188,611	151,731
Rehabilitation Hospital | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	40,999	40,218	119,358	118,151
Outpatient Rehabilitation
Disaggregation of Revenue [Line Items]
Total net operating revenues	265,927	246,644	790,491	751,999
Outpatient Rehabilitation | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	226,350	215,992	689,526	663,621
Outpatient Rehabilitation | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	40,563	36,821	120,228	111,638
Outpatient Rehabilitation | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	185,787	179,171	569,298	551,983
Outpatient Rehabilitation | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	39,577	30,652	100,965	88,378
Concentra
Disaggregation of Revenue [Line Items]
Total net operating revenues	404,481	255,881	1,173,420	763,357
Concentra | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	401,992	253,909	1,166,311	756,933
Concentra | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	455	472	1,600	1,588
Concentra | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	401,537	253,437	1,164,711	755,345
Concentra | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	$ 2,489	$ 1,972	$ 7,109	$ 6,424