Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows from Operating Activities:
Net income	$ 747,171	$ 750,698	$ 604,996
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation & amortization	416,608	398,618	375,624
Gains on sales of assets and businesses, net of losses	0	(3,615)	(7,837)
Stock-based compensation expense	48,109	39,971	31,092
Costs related to extinguishment of debt	0	0	19,730
Changes in assets & liabilities, net of effects from acquisitions and dispositions:
Accounts receivable	(87,881)	(45,814)	(105,708)
Accrued interest	9,766	(693)	4,400
Accrued and deferred income taxes	22,068	(34,394)	33,920
Other working capital accounts	74,489	(125,556)	73,912
Other assets and deferred charges	(25,671)	6,631	13,667
Other	81,139	23,295	2,449
Accrued insurance expense, net of commercial premiums paid	84,638	90,895	59,276	[1]
Payments made in settlement of self-insurance claims	(81,962)	(79,138)	(69,645)
Net cash provided by operating activities	1,288,474	1,020,898	1,035,876
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	(519,939)	(379,321)	(391,150)
Acquisition of property and businesses	(613,803)	(533,655)	(431,386)
Proceeds received from sales of assets and businesses	0	3,391	15,178
Costs incurred for purchase and implementation of information technology applications	(21,475)	0	(13,488)
Increase in capital reserves of commercial insurance subsidiary	(32,000)	(3,300)	(12,000)
Net cash used in investing activities	(1,187,217)	(912,885)	(832,846)
Cash Flows from Financing Activities:
Reduction of long-term debt	(459,183)	(68,166)	(879,129)
Additional borrowings	1,170,800	234,400	830,000
Acquisition of noncontrolling interests in majority owned businesses	(418,000)	0	0
Financing costs	(12,449)	(515)	(14,976)
Repurchase of common shares	(353,380)	(209,782)	(100,749)
Dividends paid	(38,875)	(39,532)	(29,665)
Issuance of common stock	9,503	8,441	6,863
Excess income tax benefits related to stock based compensation	45,219	47,364	33,912
Profit distributions to noncontrolling interests	(69,583)	(62,220)	(33,680)
Proceeds received from sale/leaseback of real property	0	12,765	0
Net cash used in financing activities	(125,948)	(77,245)	(187,424)
Effect of exchange rate changes on cash and cash equivalents	(2,790)	(1,609)	(775)
Increase (decrease) in cash and cash equivalents	(27,481)	29,159	14,831
Cash and cash equivalents, beginning of period	61,228	32,069	17,238
Cash and cash equivalents, end of period	33,747	61,228	32,069
Supplemental Disclosures of Cash Flow Information:
Interest paid, including early redemption premium and original issue discount write-off in 2014	107,079	107,054	130,279
Income taxes paid, net of refunds	344,611	380,658	258,612
Noncash purchases of property and equipment	$ 65,702	$ 49,086	$ 35,469

[1] General and professional liability amount is net of adjustment recorded during 2014, as discussed below.