Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities:
Net income	$ 987,632	$ 952,790	$ 827,543
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation & amortization	533,213	510,493	490,392
Loss (Gain) on sales of assets and businesses	(5,170)	1,957	(7,540)
Stock-based compensation expense	73,686	65,837	69,431
Costs related to extinguishment of debt	16,831	1,365	0
Provision for asset impairment	14,391	0	97,631
Changes in assets & liabilities, net of effects from acquisitions and dispositions:
Accounts receivable	(8,873)	(145,901)	(42,056)
Accrued interest	4,950	(10,028)	209
Accrued and deferred income taxes	(54,030)	9,593	(25,194)
Other working capital accounts	46,526	124,545	39,664
Medicare accelerated payments and deferred CARES Act and other grants	(698,762)	698,768	0
Other assets and deferred charges	(39,337)	(4,555)	(27,205)
Other	(82,075)	109,167	7,703
Accrued insurance expense, net of commercial premiums paid	186,215	159,223	105,672
Payments made in settlement of self-insurance claims	(91,502)	(113,085)	(97,781)
Net cash provided by operating activities	883,695	2,360,169	1,438,469
Cash Flows from Investing Activities:
Property and equipment additions	(855,659)	(731,307)	(634,095)
Acquisition of businesses and property	(105,415)	(52,009)	(8,005)
Inflows (outflows) from foreign exchange contracts that hedge our net U.K. investment	1,357	(21,740)	(19,763)
Proceeds received from sales of assets and businesses	25,425	8,168	9,450
Costs incurred for purchase and implementation of information technology applications	19,726	(2,902)	(21,418)
Decrease (Increase) in capital reserves of commercial insurance subsidiary	100	(100)	0
Investment in, and advances to, joint ventures and other	0	(2,672)	(14,579)
Net cash used in investing activities	(914,466)	(802,562)	(688,410)
Cash Flows from Financing Activities:
Repayments of long-term debt	(3,037,868)	(962,567)	(57,142)
Additional borrowings	3,254,974	801,599	39,220
Financing costs	(18,770)	(10,300)	0
Repurchase of common shares	(1,220,875)	(206,719)	(770,504)
Dividends paid	(65,896)	(17,344)	(53,003)
Issuance of common stock	13,372	12,318	10,806
Profit distributions to noncontrolling interests	(7,080)	(19,805)	(15,859)
Purchase of ownership interests by minority member	13,193	17,959	1,446
Net cash used in financing activities	(1,068,950)	(384,859)	(845,036)
Effect of exchange rate changes on cash and cash equivalents	(499)	739	959
(Decrease) increase in cash, cash equivalents and restricted cash	(1,100,220)	1,173,487	(94,018)
Cash, cash equivalents and restricted cash, beginning of period	1,279,154	105,667	199,685
Cash, cash equivalents and restricted cash, end of period	178,934	1,279,154	105,667
Supplemental Disclosures of Cash Flow Information:
Interest paid	75,607	112,598	157,406
Income taxes paid, net of refunds	362,978	286,247	260,622
Noncash purchases of property and equipment	$ 167,234	$ 74,854	$ 63,514