Guarantor (Cash Flow Statements) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net cash flows provided by operating activities	$ 295,652,000	$ 243,423,000	$ 230,575,000
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	(277,388,000)	(239,223,000)	(53,690,000)
Acquisition of property and equipment	(28,864,000)	(22,170,000)	(19,275,000)
Proceeds from sale of interests in surgery centers	7,309,000	7,026,000	60,000
Net cash flows used in investing activities	(298,943,000)	(254,367,000)	(72,905,000)
Cash flows from financing activities:
Proceeds from long-term borrowings	565,566,000	288,869,000	176,619,000
Repayment on long-term borrowings	(394,164,000)	(129,107,000)	(195,960,000)
Distributions to noncontrolling interests	(162,941,000)	(138,724,000)	(132,110,000)
Net cash flows provided by (used in) financing activities	8,971,000	17,515,000	(152,900,000)
Net increase (decrease) in cash and cash equivalents	5,680,000	6,571,000	4,770,000
Cash and cash equivalents, beginning of period	40,718,000	34,147,000	29,377,000
Cash and cash equivalents, end of period	46,398,000	40,718,000	34,147,000
Parent Company [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	(83,605,000)	(67,911,000)	20,905,000
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	(90,029,000)	(84,597,000)	0
Acquisition of property and equipment	(3,681,000)	(2,858,000)	(2,138,000)
Proceeds from sale of interests in surgery centers	0	0	0
Net cash flows used in investing activities	(93,710,000)	(87,455,000)	(2,138,000)
Cash flows from financing activities:
Proceeds from long-term borrowings	560,000,000	281,100,000	173,800,000
Repayment on long-term borrowings	(381,220,000)	(118,100,000)	(187,100,000)
Distributions to noncontrolling interests	0	0	0
Capital contributions	0	0
Changes In Intercompany Balances	(2,666,000)	(178,000)	(799,000)
Other financing activities, net	(70,000)	(3,609,000)	(1,573,000)
Net cash flows provided by (used in) financing activities	176,044,000	159,213,000	(15,672,000)
Net increase (decrease) in cash and cash equivalents	(1,271,000)	3,847,000	3,095,000
Cash and cash equivalents, beginning of period	8,530,000	4,683,000	1,588,000
Cash and cash equivalents, end of period	7,259,000	8,530,000	4,683,000
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	182,851,000	151,558,000	143,049,000
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	(280,189,000)	(243,429,000)	(54,420,000)
Acquisition of property and equipment	0	0	0
Proceeds from sale of interests in surgery centers	7,309,000	7,274,000	60,000
Net cash flows used in investing activities	(272,880,000)	(236,155,000)	(54,360,000)
Cash flows from financing activities:
Proceeds from long-term borrowings	0	0	0
Repayment on long-term borrowings	0	0	0
Distributions to noncontrolling interests	0	0	(88,689,000)
Capital contributions	90,029,000	84,597,000
Changes In Intercompany Balances	0		0
Other financing activities, net	0	0	0
Net cash flows provided by (used in) financing activities	90,029,000	84,597,000	(88,689,000)
Net 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
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	379,257,000	311,334,000	298,359,000
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	0	0	0
Acquisition of property and equipment	(25,183,000)	(19,312,000)	(17,137,000)
Proceeds from sale of interests in surgery centers	0	(248,000)	0
Net cash flows used in investing activities	(25,183,000)	(19,560,000)	(17,137,000)
Cash flows from financing activities:
Proceeds from long-term borrowings	5,566,000	7,769,000	2,819,000
Repayment on long-term borrowings	(12,944,000)	(11,007,000)	(8,860,000)
Distributions to noncontrolling interests	(345,792,000)	(290,282,000)	(275,159,000)
Capital contributions	0	0
Changes In Intercompany Balances	2,666,000	178,000	799,000
Other financing activities, net	3,381,000	4,292,000	854,000
Net cash flows provided by (used in) financing activities	(347,123,000)	(289,050,000)	(279,547,000)
Net increase (decrease) in cash and cash equivalents	6,951,000	2,724,000	1,675,000
Cash and cash equivalents, beginning of period	32,188,000	29,464,000	27,789,000
Cash and cash equivalents, end of period	39,139,000	32,188,000	29,464,000
Consolidation, Eliminations [Member]
Cash flows from operating activities:
Net cash flows provided by operating activities	(182,851,000)	(151,558,000)	(231,738,000)
Cash flows from investing activities:
Acquisition of interests in surgery centers and related transactions	92,830,000	88,803,000	730,000
Acquisition of property and equipment	0	0	0
Proceeds from sale of interests in surgery centers	0	0	0
Net cash flows used in investing activities	92,830,000	88,803,000	730,000
Cash flows from financing activities:
Proceeds from long-term borrowings	0	0	0
Repayment on long-term borrowings	0	0	0
Distributions to noncontrolling interests	182,851,000	151,558,000	231,738,000
Capital contributions	(90,029,000)	(84,597,000)
Changes In Intercompany Balances	0		0
Other financing activities, net	(2,801,000)	(4,206,000)	(730,000)
Net cash flows provided by (used in) financing activities	90,021,000	62,755,000	231,008,000
Net 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
Consolidated Entities [Member]
Cash flows from financing activities:
Other financing activities, net	510,000	(3,523,000)	(1,449,000)
Cash and cash equivalents, beginning of period			$ 29,377,000