Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash Flows from Operating Activities:
Net income	$ 5,463	$ 15,324
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,166	9,355
Provision for doubtful accounts	5,913	3,162
Non-cash compensation	2,482	1,910
401(k) employer match	2,347	1,403
Loss on disposal of property and equipment	505	656
Deferred income taxes	1,421	399
Equity in earnings of equity investments	(305)	(323)
Amortization of deferred debt issuance costs	394	394
Return on equity investment	150	240
Changes in operating assets and liabilities, net of impact of acquisitions:
Patient accounts receivable	(19,686)	(3,536)
Other current assets	1,335	5,112
Other assets	(39)	(493)
Accounts payable	(87)	2,889
Accrued expenses	2,051	17,605
Other long-term obligations	(239)	(1,543)
Net cash provided by operating activities	11,871	52,554
Cash Flows from Investing Activities:
Proceeds from sale of deferred compensation plan assets	230	853
Purchases of deferred compensation plan assets	(47)	(219)
Purchases of property and equipment	(10,236)	(16,580)
Net cash used in investing activities	(10,053)	(15,946)
Cash Flows from Financing Activities:
Proceeds from issuance of stock upon exercise of stock options and warrants		96
Proceeds from issuance of stock to employee stock purchase plan	962	1,578
Tax benefit from stock option exercises	(944)	(82)
Principal payments of long-term obligations	(8,550)	(9,627)
Net cash used in financing activities	(8,532)	(8,035)
Net (decrease) increase in cash and cash equivalents	(6,714)	28,573
Cash and cash equivalents at beginning of period	48,004	120,295
Cash and cash equivalents at end of period	41,290	148,868
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	3,388	3,490
Cash paid for income taxes, net of refunds received	$ 1,150	$ 2,793