Supplemental Condensed Consolidating Statements of Cash flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements Captions [Line Items]
Net cash (used in) provided by operating activities	$ 1,020,898	$ 1,035,876	$ 884,241
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	(379,321)	(391,150)	(358,493)
Acquisition of property and businesses	(533,655)	(431,386)	(12,636)
Proceeds received from sale of assets and businesses	3,391	15,178	37,482
Costs incurred for purchase and implementation of electronic health records application	0	(13,488)	(49,811)
Increase in insurance subsidiary investments	(3,300)	(12,000)	0
Net cash used in investing activities	(912,885)	(832,846)	(383,458)
Cash Flows from Financing Activities:
Reduction of long-term debt	(68,166)	(879,129)	(440,224)
Additional borrowings	234,400	830,000	15,761
Financing costs	(515)	(14,976)	(231)
Repurchase of common shares	(209,782)	(100,749)	(27,201)
Dividends paid	(39,532)	(29,665)	(19,621)
Issuance of common stock	8,441	6,863	5,708
Excess income tax benefits related to stock based compensation	47,364	33,912	20,121
Profit distributions to noncontrolling interests	(62,220)	(33,680)	(61,329)
Proceeds received from sale/leaseback of real property	12,765	0	0
Changes in intercompany balances with affiliates, net	0	0	0
Net cash used in financing activities	(77,245)	(187,424)	(507,016)
Effect of exchange rate changes on cash and cash equivalents	(1,609)	(775)	0
Increase (decrease) in cash and cash equivalents	29,159	14,831	(6,233)
Cash and cash equivalents, beginning of period	32,069	17,238	23,471
Cash and cash equivalents, end of period	61,228	32,069	17,238
Parent
Condensed Financial Statements Captions [Line Items]
Net cash (used in) provided by operating activities	(21,287)	18,579	17,946
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	0	0	0
Acquisition of property and businesses		0	0
Proceeds received from sale of assets and businesses	0	0	0
Costs incurred for purchase and implementation of electronic health records application		0	0
Increase in insurance subsidiary investments	0	0
Net cash used in investing activities	0	0	0
Cash Flows from Financing Activities:
Reduction of long-term debt	(42,133)	(866,748)	(429,996)
Additional borrowings	234,400	830,000	15,761
Financing costs	(515)	(14,976)	(231)
Repurchase of common shares	(209,782)	(100,749)	(27,201)
Dividends paid	(39,532)	(29,665)	(19,621)
Issuance of common stock	8,441	6,863	5,708
Excess income tax benefits related to stock based compensation	47,364	33,912	20,121
Profit distributions to noncontrolling interests	0	0	0
Proceeds received from sale/leaseback of real property	0
Changes in intercompany balances with affiliates, net	23,044	122,784	417,513
Net cash used in financing activities	21,287	(18,579)	(17,946)
Effect of exchange rate changes on cash and cash equivalents	0	0
Increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents, beginning of period	0	0	0
Cash and cash equivalents, end of period	0	0	0
Guarantors
Condensed Financial Statements Captions [Line Items]
Net cash (used in) provided by operating activities	655,439	687,101	587,083
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	(209,355)	(230,102)	(269,419)
Acquisition of property and businesses	(513,382)	(422,081)	(8,094)
Proceeds received from sale of assets and businesses	647	11,450	7,916
Costs incurred for purchase and implementation of electronic health records application		(13,488)	(49,811)
Increase in insurance subsidiary investments	(3,300)	(12,000)
Net cash used in investing activities	(725,390)	(666,221)	(319,408)
Cash Flows from Financing Activities:
Reduction of long-term debt	(3,459)	(867)	(109)
Additional borrowings	0	0	0
Financing costs	0	0	0
Repurchase of common shares	0	0	0
Dividends paid	0	0	0
Issuance of common stock	0	0	0
Excess income tax benefits related to stock based compensation	0	0	0
Profit distributions to noncontrolling interests	0	0	0
Proceeds received from sale/leaseback of real property	0
Changes in intercompany balances with affiliates, net	100,427	(5,444)	(271,525)
Net cash used in financing activities	96,968	(6,311)	(271,634)
Effect of exchange rate changes on cash and cash equivalents	(1,609)	(775)
Increase (decrease) in cash and cash equivalents	25,408	13,794	(3,959)
Cash and cash equivalents, beginning of period	21,784	7,990	11,949
Cash and cash equivalents, end of period	47,192	21,784	7,990
Non Guarantors
Condensed Financial Statements Captions [Line Items]
Net cash (used in) provided by operating activities	386,746	330,196	279,212
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	(169,966)	(161,048)	(89,074)
Acquisition of property and businesses	(20,273)	(9,305)	(4,542)
Proceeds received from sale of assets and businesses	2,744	3,728	29,566
Costs incurred for purchase and implementation of electronic health records application		0	0
Increase in insurance subsidiary investments	0	0
Net cash used in investing activities	(187,495)	(166,625)	(64,050)
Cash Flows from Financing Activities:
Reduction of long-term debt	(22,574)	(11,514)	(10,119)
Additional borrowings	0	0	0
Financing costs	0	0	0
Repurchase of common shares	0	0	0
Dividends paid	0	0	0
Issuance of common stock	0	0	0
Excess income tax benefits related to stock based compensation	0	0	0
Profit distributions to noncontrolling interests	(62,220)	(33,680)	(61,329)
Proceeds received from sale/leaseback of real property	12,765
Changes in intercompany balances with affiliates, net	(123,471)	(117,340)	(145,988)
Net cash used in financing activities	(195,500)	(162,534)	(217,436)
Effect of exchange rate changes on cash and cash equivalents	0	0
Increase (decrease) in cash and cash equivalents	3,751	1,037	(2,274)
Cash and cash equivalents, beginning of period	10,285	9,248	11,522
Cash and cash equivalents, end of period	14,036	10,285	9,248
Consolidating Adjustments
Condensed Financial Statements Captions [Line Items]
Net cash (used in) provided by operating activities	0	0	0
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	0	0	0
Acquisition of property and businesses		0	0
Proceeds received from sale of assets and businesses	0	0	0
Costs incurred for purchase and implementation of electronic health records application		0	0
Increase in insurance subsidiary investments	0	0
Net cash used in investing activities	0	0	0
Cash Flows from Financing Activities:
Reduction of long-term debt	0	0	0
Additional borrowings	0	0	0
Financing costs	0	0	0
Repurchase of common shares	0	0	0
Dividends paid	0	0	0
Issuance of common stock	0	0	0
Excess income tax benefits related to stock based compensation	0	0	0
Profit distributions to noncontrolling interests	0	0	0
Proceeds received from sale/leaseback of real property	0
Changes in intercompany balances with affiliates, net	0	0	0
Net cash used in financing activities	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0
Increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents, beginning of period	0	0	0
Cash and cash equivalents, end of period	$ 0	$ 0	$ 0