Financial Information for the Company and Its Subsidiaries (Cash Flow Statements) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net cash flows provided by operating activities	$ 153,581	$ 152,550
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	(24,437)	(18,346)
Acquisition of property and equipment	(16,075)	(12,472)
Proceeds from sale of interests in surgery centers	2,092	0
Other	(1,381)	55
Net cash flows used in investing activities	(39,801)	(30,763)
Cash flows from financing activities:
Proceeds from long-term borrowings	74,246	70,922
Repayment on long-term borrowings	(102,326)	(96,222)
Distributions to noncontrolling interests	(92,010)	(91,526)
Changes In Intercompany Balances	0	0
Other financing activities, net	381	(11,436)
Net cash flows provided by (used in) financing activities	(119,709)	(128,262)
Net increase (decrease) in cash and cash equivalents	(5,929)	(6,475)
Cash and cash equivalents, beginning of period	50,840	46,398
Cash and cash equivalents, end of period	44,911	39,923
Consolidation, Eliminations [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	(179,130)	(187,493)
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	2,443	78
Acquisition of property and equipment	0	0
Proceeds from sale of interests in surgery centers	0
Other	0	0
Net cash flows used in investing activities	2,443	78
Cash flows from financing activities:
Proceeds from long-term borrowings	0	0
Repayment on long-term borrowings	0	0
Distributions to noncontrolling interests	179,130	187,493
Changes In Intercompany Balances	0	0
Other financing activities, net	(2,443)	(78)
Net cash flows provided by (used in) financing activities	176,687	187,415
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Parent Company [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	27,919	32,189
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	0	0
Acquisition of property and equipment	(1,949)	(1,189)
Proceeds from sale of interests in surgery centers	0
Other	(1,259)	0
Net cash flows used in investing activities	(3,208)	(1,189)
Cash flows from financing activities:
Proceeds from long-term borrowings	70,000	66,700
Repayment on long-term borrowings	(96,358)	(89,224)
Distributions to noncontrolling interests	0	0
Changes In Intercompany Balances	(1,020)	1,431
Other financing activities, net	(207)	(12,371)
Net cash flows provided by (used in) financing activities	(27,585)	(33,464)
Net increase (decrease) in cash and cash equivalents	(2,874)	(2,464)
Cash and cash equivalents, beginning of period	6,710	7,259
Cash and cash equivalents, end of period	3,836	4,795
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	102,284	102,630
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	(26,880)	(18,424)
Acquisition of property and equipment	0	0
Proceeds from sale of interests in surgery centers	2,092
Other	(122)	55
Net cash flows used in investing activities	(24,910)	(18,369)
Cash flows from financing activities:
Proceeds from long-term borrowings	0	0
Repayment on long-term borrowings	0	0
Distributions to noncontrolling interests	(76,846)	(84,863)
Changes In Intercompany Balances	0	0
Other financing activities, net	(528)	602
Net cash flows provided by (used in) financing activities	(77,374)	(84,261)
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	202,508	205,224
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	0	0
Acquisition of property and equipment	(14,126)	(11,283)
Proceeds from sale of interests in surgery centers	0
Other	0	0
Net cash flows used in investing activities	(14,126)	(11,283)
Cash flows from financing activities:
Proceeds from long-term borrowings	4,246	4,222
Repayment on long-term borrowings	(5,968)	(6,998)
Distributions to noncontrolling interests	(194,294)	(194,156)
Changes In Intercompany Balances	1,020	(1,431)
Other financing activities, net	3,559	411
Net cash flows provided by (used in) financing activities	(191,437)	(197,952)
Net increase (decrease) in cash and cash equivalents	(3,055)	(4,011)
Cash and cash equivalents, beginning of period	44,130	39,139
Cash and cash equivalents, end of period	$ 41,075	$ 35,128