Segment Reporting - Segment Reporting Information, Reconciliation of Net Operating Revenues to Segment Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Net operating revenues	$ 1,173.9	$ 1,161.6	$ 3,430.0	$ 3,420.6
Operating expenses:
Salaries and benefits	664.9	660.8	1,995.9	1,904.5
Other operating expenses	163.4	156.6	471.3	456.5
Supplies	52.5	42.9	148.8	124.7
Occupancy costs	20.3	21.8	60.8	61.7
Total operating expenses	1,001.4	989.7	2,978.0	2,890.7
Other income	(2.5)	(21.0)	(6.4)	(26.9)
Equity in net income of nonconsolidated affiliates	(1.0)	(1.2)	(2.5)	(5.5)
Noncontrolling interests	22.4	21.9	58.9	64.5
Inpatient Rehabilitation
Segment Reporting Information [Line Items]
Net operating revenues	899.4	872.3	2,633.1	2,616.3
Operating expenses:
Salaries and benefits	475.0	459.1	1,408.7	1,347.7
Other operating expenses	135.5	131.3	394.5	386.1
Supplies	45.3	37.0	126.9	109.3
Occupancy costs	15.3	17.0	46.0	49.1
Total operating expenses	671.1	644.4	1,976.1	1,892.2
Other income	(2.1)	(1.8)	(3.9)	(6.5)
Equity in net income of nonconsolidated affiliates	(0.9)	(1.0)	(2.1)	(4.5)
Noncontrolling interests	22.1	20.1	58.0	60.6
Segment Adjusted EBITDA	209.2	210.6	605.0	674.5
Capital expenditures	90.4	103.6	262.6	266.0
Home Health and Hospice
Segment Reporting Information [Line Items]
Net operating revenues	274.5	289.3	796.9	804.3
Operating expenses:
Cost of services sold (excluding depreciation and amortization)	121.8	136.4	389.4	372.8
Support and overhead costs	100.7	99.6	299.2	278.1
Total operating expenses	222.5	236.0	688.6	650.9
Other income	0.0	0.0	0.0	0.0
Equity in net income of nonconsolidated affiliates	(0.1)	(0.2)	(0.4)	(1.0)
Noncontrolling interests	0.3	2.7	0.9	8.2
Segment Adjusted EBITDA	51.8	50.8	107.8	146.2
Capital expenditures	$ 0.5	$ 3.1	$ 2.6	$ 11.1