Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 517.2	$ 368.8	$ 445.8
Loss from discontinued operations, net of tax	0.4	0.0	0.6
Adjustments to reconcile net income to net cash provided by operating activities—
Provision for government, class action, and related settlements	0.0	2.8	0.0
Depreciation and amortization	256.6	243.0	218.7
Amortization of debt-related items	7.8	7.2	4.5
Loss on early extinguishment of debt	1.0	2.3	7.7
Equity in net income of nonconsolidated affiliates	(4.0)	(3.5)	(6.7)
Distributions from nonconsolidated affiliates	2.9	3.8	6.6
Stock-based compensation	32.8	29.5	114.4
Deferred tax expense	27.8	52.4	40.0
Gain on consolidation of Yuma Rehabilitation Hospital	0.0	0.0	(19.2)
Other, net	(8.2)	5.9	7.4
Changes in assets and liabilities, net of acquisitions —
Accounts receivable	(64.3)	(38.1)	(22.9)
Prepaid expenses and other assets	(42.0)	0.1	(35.4)
Accounts payable	14.9	13.6	(6.1)
Accrued payroll	(38.1)	92.0	13.2
Other liabilities	11.5	(74.9)	(128.9)
Net cash used in operating activities of discontinued operations	(0.5)	(0.2)	(4.4)
Total adjustments	198.2	335.9	188.9
Net cash provided by operating activities	715.8	704.7	635.3
Cash flows from investing activities:
Acquisition of businesses, net of cash acquired	(118.6)	(1.1)	(231.5)
Purchases of property and equipment	(528.9)	(396.0)	(372.4)
Additions to capitalized software costs	(15.8)	(8.7)	(13.0)
Purchases of intangible assets	(6.5)	(3.5)	(18.7)
Proceeds from sale of restricted investments	0.0	12.6	17.6
Purchases of restricted investments	(9.0)	(8.7)	(32.9)
Other, net	12.5	(2.1)	(6.5)
Net cash used in investing activities	(666.3)	(407.5)	(657.4)
Cash flows from financing activities:
Proceeds from bond issuance	0.0	992.5	1,000.0
Principal payments on debt, including pre-payments	(214.5)	(718.3)	(519.5)
Borrowings on revolving credit facility	300.0	330.0	635.0
Payments on revolving credit facility	(100.0)	(375.0)	(620.0)
Principal payments under finance lease obligations	(51.8)	(22.5)	(19.5)
Debt amendment and issuance costs	0.0	(20.3)	(21.5)
Repurchases of common stock, including fees and expenses	0.0	(6.1)	(45.9)
Dividends paid on common stock	(112.4)	(111.9)	(108.7)
Purchase of equity interests in consolidated affiliates	0.0	(162.3)	(162.9)
Distributions paid to noncontrolling interests of consolidated affiliates	(102.9)	(72.2)	(79.8)
Taxes paid on behalf of employees for shares withheld	(16.4)	(15.7)	(16.6)
Contributions from noncontrolling interests of consolidated affiliates	57.2	34.9	15.9
Other, net	0.7	1.0	(8.3)
Net cash (used in) provided by financing activities	(240.1)	(145.9)	48.2
(Decrease) increase in cash, cash equivalents, and restricted cash	(190.6)	151.3	26.1
Cash, cash equivalents. and restricted cash at beginning of year	310.9	159.6	133.5
Cash, cash equivalents, and restricted cash at end of year	120.3	310.9	159.6
Reconciliation of Cash, Cash Equivalents, and Restricted Cash
Cash and cash equivalents at beginning of period	224.0	94.8	69.2
Restricted cash at beginning of period	65.4	57.4	59.0
Restricted cash included in other long-term assets at beginning of period	21.5	7.4	5.3
Cash, cash equivalents. and restricted cash at beginning of year	310.9	159.6	133.5
Cash and cash equivalents at end of period	54.8	224.0	94.8
Restricted cash at end of period	65.1	65.4	57.4
Restricted cash included in other long-term assets at end of period	0.4	21.5	7.4
Cash, cash equivalents, and restricted cash at end of year	120.3	310.9	159.6
Supplemental cash flow information:
Interest	(168.4)	(168.4)	(155.7)
Income tax refunds	1.8	1.4	0.1
Income tax payments	$ (131.4)	$ (34.3)	(104.2)
Supplemental schedule of noncash financing activities:
Adoption of ASC 842			$ 349.4