Supplemental Cash Flow Information (Summary Of Supplemental Cash Flow Information) (Details) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash Paid During The Period For
Interest	$ 10,012	$ 8,102
Income taxes, net of refunds	9,372	14,647
Noncash Investing and Financing Activities
Increase (decrease) in accounts payable associated with acquisition of property and equipment	185	(712)
Capital lease obligations	326	3,542
Effect Of Acquisitions And Related Transactions [Abstract]
Assets acquired, net of cash and adjustments	310,191	64,954
Liabilities assumed and noncontrolling interests	(121,691)	(23,339)
Payment for interests in surgery centers and related transactions	$ 188,500	$ 41,615