Segment Reporting Segment Reporting - Table 3 (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
General and administrative expenses									$ (133.3)	$ (124.8)	$ (119.1)
Depreciation and amortization									(139.7)	(107.7)	(94.7)
Loss on disposal or impairment of assets									(2.6)	(6.7)	(5.9)
Government, class action, and related settlements									(7.5)	1.7	23.5
Professional fees - accounting, tax, and legal									(3.0)	(9.3)	(9.5)
Loss on early extinguishment of debt	$ (2.4)		$ (18.8)	$ (1.2)					(22.4)	(13.2)	(2.4)
Interest expense and amortization of debt discounts and fees									(142.9)	(109.2)	(100.4)
Gain on consolidation of former equity method hospital									0.0	27.2	0.0
Net income attributable to noncontrolling interests	$ 18.8	$ 17.1	$ 17.3	$ 16.5	$ 15.4	$ 14.7	$ 14.8	$ 14.8	69.7	59.7	57.8
Gain related to SCA equity interest									3.2	0.0	0.0
Income from continuing operations before income tax expense									395.6	386.9	395.2
Other Expenses									0.0	0.0	0.2
Inpatient Rehabilitation Hospital and Home Health and Hospice [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment Adjusted EBITDA									774.1	669.2	645.7
Fairlawn Rehabilitation Hospital [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain on consolidation of former equity method hospital									$ 0.0	$ 27.2	$ 0.0