Segment Reporting - Table 5 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	$ 1,067.6	$ 981.6	$ 3,181.3	$ 2,905.1
Inpatient Rehabilitation Segment [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	825.6	783.5	2,500.5	2,338.9
Inpatient Rehabilitation Segment [Member] | Inpatient [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	798.4	758.2	2,425.1	2,262.4
Inpatient Rehabilitation Segment [Member] | Outpatient and other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	27.2	25.3	75.4	76.5
Home Health and Hospice Segment [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	242.0	198.1	680.8	566.2
Home Health and Hospice Segment [Member] | Home health [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	209.2	180.3	599.3	516.1
Home Health and Hospice Segment [Member] | Hospice [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net operating revenues	$ 32.8	$ 17.8	$ 81.5	$ 50.1