Condensed Consolidated Statements of Cash Flows - Entity [Domain] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash Flows from Operating Activities:
Net income	$ 395,727	$ 318,466
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation & amortization	196,255	184,050
Stock-based compensation expense	20,474	14,945
Gains on sales of assets and businesses, net of losses	0	(10,134)
Changes in assets & liabilities, net of effects from acquisitions and dispositions:
Accounts receivable	(95,013)	(61,865)
Accrued interest	(1,520)	(271)
Accrued and deferred income taxes	10,870	(9,435)
Other working capital accounts	(10,899)	17,739
Other assets and deferred charges	4,074	10,415
Other	2,163	(4,092)
Accrued insurance expense, net of commercial premiums paid	50,511	38,520
Payments made in settlement of self-insurance claims	(41,039)	(39,922)
Net cash provided by operating activities	531,603	458,416
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	(170,580)	(186,786)
Proceeds received from sale of assets and businesses	0	11,450
Acquisition of property and businesses	(34,500)	(71,000)
Costs incurred for purchase and implementation of electronic health records application	0	(8,399)
Net cash provided by (used in) investing activities	(205,080)	(254,735)
Cash Flows from Financing Activities:
Reduction of long-term debt	(255,658)	(179,126)
Additional borrowings	5,200	0
Repurchase of common shares	(68,157)	(35,773)
Dividends paid	(19,804)	(9,884)
Issuance of common stock	4,039	3,287
Excess income tax benefits related to stock-based compensation	28,489	28,493
Profit distributions to noncontrolling interests	(23,295)	(13,184)
Proceeds received from sale/leaseback of real property	12,765	0
Net cash (used in) provided by financing activities	(316,421)	(206,187)
Effect of exchange rate changes on cash and cash equivalents	293	0
Increase (decrease) in cash and cash equivalents	10,395	(2,506)
Cash and cash equivalents, beginning of period	32,069	17,238
Cash and cash equivalents, end of period	42,464	14,732
Supplemental Disclosures of Cash Flow Information:
Interest paid	55,718	60,078
Income taxes paid, net of refunds	166,637	156,434
Noncash purchases of property and equipment	$ 34,488	$ 58,020