Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total net operating revenues	$ 1,414,632	$ 1,324,631
Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	1,302,871	1,222,332
Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	373,565	353,581
Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	929,306	868,751
Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	111,761	102,299
Operating Segments | Critical Illness Recovery Hospital
Disaggregation of Revenue [Line Items]
Total net operating revenues	500,521	457,534
Operating Segments | Critical Illness Recovery Hospital | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	497,456	455,128
Operating Segments | Critical Illness Recovery Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	241,509	238,169
Operating Segments | Critical Illness Recovery Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	255,947	216,959
Operating Segments | Critical Illness Recovery Hospital | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	3,065	2,406
Operating Segments | Rehabilitation Hospital
Disaggregation of Revenue [Line Items]
Total net operating revenues	182,019	154,558
Operating Segments | Rehabilitation Hospital | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	172,188	145,221
Operating Segments | Rehabilitation Hospital | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	90,752	74,579
Operating Segments | Rehabilitation Hospital | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	81,436	70,642
Operating Segments | Rehabilitation Hospital | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	9,831	9,337
Operating Segments | Outpatient Rehabilitation
Disaggregation of Revenue [Line Items]
Total net operating revenues	255,249	246,905
Operating Segments | Outpatient Rehabilitation | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	237,722	228,192
Operating Segments | Outpatient Rehabilitation | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	40,832	40,278
Operating Segments | Outpatient Rehabilitation | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	196,890	187,914
Operating Segments | Outpatient Rehabilitation | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	17,527	18,713
Operating Segments | Concentra
Disaggregation of Revenue [Line Items]
Total net operating revenues	398,535	396,321
Operating Segments | Concentra | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	395,505	393,791
Operating Segments | Concentra | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	472	555
Operating Segments | Concentra | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	395,033	393,236
Operating Segments | Concentra | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	3,030	2,530
Other
Disaggregation of Revenue [Line Items]
Total net operating revenues	78,308	69,313
Other | Patient services revenue
Disaggregation of Revenue [Line Items]
Total net operating revenues	0	0
Other | Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	0	0
Other | Non-Medicare
Disaggregation of Revenue [Line Items]
Total net operating revenues	0	0
Other | Other revenues
Disaggregation of Revenue [Line Items]
Total net operating revenues	$ 78,308	$ 69,313