Supplemental Data (unaudited) - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 333,040	$ 830,555	$ 1,033,082
Changes in operating and intercompany assets and liabilities and non-cash items included in net income	1,438,600	1,082,611	939,044
Net cash provided by operating activities	1,771,640	1,913,166	1,972,126
Cash flows from investing activities:
Additions of property and equipment	(987,138)	(905,250)	(829,095)
Acquisitions and divestitures, net	(183,156)
Proceeds from asset sales	150,205
Investments and other items, net	14,446	252,061	126,558
Net cash used in investing activities	(1,005,643)	(1,364,732)	(1,201,668)
Cash flows from financing activities:
Long-term debt and related financing costs, net	694,777	154,848	(124,442)
Intercompany	0	0	0
Other items	(1,320,131)	(921,105)	(1,227,539)
Net cash used in financing activities	(625,354)	(766,257)	(1,351,981)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	(3,350)	254	4,276
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	137,293	(217,569)	(577,247)
Cash, cash equivalents and restricted cash of continuing operations at beginning of the year	518,920	683,463	1,244,917
Cash, cash equivalents and restricted cash of continuing operations at end of the year	415,420	518,920	683,463
Physician Groups
Cash flows from operating activities:
Net income	37,373
Changes in operating and intercompany assets and liabilities and non-cash items included in net income	81,722
Net cash provided by operating activities	119,095
Cash flows from investing activities:
Additions of property and equipment	(2,746)
Acquisitions and divestitures, net	0
Proceeds from asset sales	0
Investments and other items, net	(154)
Net cash used in investing activities	(2,900)
Cash flows from financing activities:
Long-term debt and related financing costs, net	0
Intercompany	25,296
Other items	0
Net cash used in financing activities	25,296
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	0
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	141,491
Cash, cash equivalents and restricted cash of continuing operations at beginning of the year	0
Cash, cash equivalents and restricted cash of continuing operations at end of the year	0	0
Unrestricted Subsidiaries
Cash flows from operating activities:
Net income	92
Changes in operating and intercompany assets and liabilities and non-cash items included in net income	(92)
Net cash provided by operating activities	0
Cash flows from investing activities:
Additions of property and equipment	0
Acquisitions and divestitures, net	0
Proceeds from asset sales	0
Investments and other items, net	0
Net cash used in investing activities	0
Cash flows from financing activities:
Long-term debt and related financing costs, net	0
Intercompany	0
Other items	0
Net cash used in financing activities	0
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	0
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	0
Cash, cash equivalents and restricted cash of continuing operations at beginning of the year	0
Cash, cash equivalents and restricted cash of continuing operations at end of the year	0	0
Company and Restricted Subsidiaries(1)
Cash flows from operating activities:
Net income	295,575
Changes in operating and intercompany assets and liabilities and non-cash items included in net income	1,356,970
Net cash provided by operating activities	1,652,545
Cash flows from investing activities:
Additions of property and equipment	(984,392)
Acquisitions and divestitures, net	(183,156)
Proceeds from asset sales	150,205
Investments and other items, net	14,600
Net cash used in investing activities	(1,002,743)
Cash flows from financing activities:
Long-term debt and related financing costs, net	694,777
Intercompany	(25,296)
Other items	(1,320,131)
Net cash used in financing activities	(650,650)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	(3,350)
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	(4,198)
Cash, cash equivalents and restricted cash of continuing operations at beginning of the year	518,920
Cash, cash equivalents and restricted cash of continuing operations at end of the year	415,420	518,920
Discontinued Operations
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	240,793	(53,026)	(15,793)
Discontinued Operations | Physician Groups
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	141,491
Discontinued Operations | Unrestricted Subsidiaries
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	0
Discontinued Operations | Company and Restricted Subsidiaries(1)
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	99,302
Continuing Operations
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	(103,500)	$ (164,543)	$ (561,454)
Continuing Operations | Physician Groups
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	0
Continuing Operations | Unrestricted Subsidiaries
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	0
Continuing Operations | Company and Restricted Subsidiaries(1)
Cash flows from financing activities:
Less: Net increase (decrease) in cash, cash equivalents and restricted cash from discontinued operations	$ (103,500)