Supplemental Data - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income		$ 427,410	$ 863,330	$ 757,201
Changes in operating and intercompany assets and liabilities and non-cash items included in net income		1,129,790	596,077	1,016,140
Net cash provided by operating activities		1,557,200	1,459,407	1,773,341
Cash flows from investing activities:
Additions of property and equipment		(707,998)	(641,330)	(617,597)
Acquisitions and divestitures, net		(96,469)
Proceeds from asset sales		19,715	8,791	62,258
Investments and other items		(97,032)	(373,096)	(11,149)
Net cash used in investing activities		(881,784)	(1,277,729)	(876,882)
Cash flows from financing activities:
Long-term debt and related financing costs, net		619,698	(7,989)	(438,007)
Other items		(758,668)	(156,990)	(44,984)
Net cash used in financing activities		(138,970)	(164,979)	(482,991)
Effect of exchange rate changes on cash		(2,571)	2,293	(967)
Net increase in cash and cash equivalents		533,875	18,992	412,501
Cash and cash equivalents at beginning of the year		965,241	946,249	533,748
Cash and cash equivalents at end of the year		1,499,116	965,241	$ 946,249
Physician Groups
Cash flows from operating activities:
Net income		51,697
Changes in operating and intercompany assets and liabilities and non-cash items included in net income		(101,217)
Net cash provided by operating activities		(49,520)
Cash flows from investing activities:
Additions of property and equipment		(355)
Investments and other items		(3,124)
Net cash used in investing activities		(3,479)
Cash flows from financing activities:
Intercompany borrowing		28,796
Net cash used in financing activities		28,796
Net increase in cash and cash equivalents		(24,203)
Cash and cash equivalents at beginning of the year		112,448
Cash and cash equivalents at end of the year		88,245	112,448
Unrestricted Subsidiaries
Cash flows from operating activities:
Net income		8
Changes in operating and intercompany assets and liabilities and non-cash items included in net income		(8)
Company and Restricted Subsidiaries
Cash flows from operating activities:
Net income	[1]	375,705
Changes in operating and intercompany assets and liabilities and non-cash items included in net income	[1]	1,231,015
Net cash provided by operating activities	[1]	1,606,720
Cash flows from investing activities:
Additions of property and equipment	[1]	(707,643)
Acquisitions and divestitures, net	[1]	(96,469)
Proceeds from asset sales	[1]	19,715
Investments and other items	[1]	(93,908)
Net cash used in investing activities	[1]	(878,305)
Cash flows from financing activities:
Long-term debt and related financing costs, net	[1]	619,698
Intercompany borrowing	[1]	(28,796)
Other items	[1]	(758,668)
Net cash used in financing activities	[1]	(167,766)
Effect of exchange rate changes on cash	[1]	(2,571)
Net increase in cash and cash equivalents	[1]	558,078
Cash and cash equivalents at beginning of the year	[1]	852,793
Cash and cash equivalents at end of the year	[1]	$ 1,410,871	$ 852,793

[1] After the elimination of the unrestricted subsidiaries and the physician groups