Supplemental Cash Flow Information (Summary Of Supplemental Cash Flow Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash Paid During The Period For [Abstract]
Interest	$ 6,204	$ 3,794
Income taxes, net of refunds	1,778	131
Noncash Investing and Financing Activities
Increase (decrease) in accounts payable associated with acquisition of property and equipment	(392)	(908)
Capital lease obligations	120	164
Effect Of Acquisitions And Related Transactions [Abstract]
Assets acquired, net of cash and adjustments	12,911	6,838
Liabilities assumed and noncontrolling interests	(4,768)	(3,143)
Supplemental Deferred Purchase Price	1,714	0
Payment for interests in surgery centers and related transactions	$ 9,857	$ 3,695