Consolidated Statements of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 82,748	$ 71,524
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	54,246	52,363
Goodwill impairment		1,684
Amortization of debt issuance costs and other non-cash interest	2,141	2,136
Deferred income taxes	10,606	8,350
Income tax benefit of equity compensation	(1,811)	(2,239)
Non-cash equity compensation	5,231	4,841
Other non-cash items	1,234	125
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	51,318	(24,329)
Accounts payable, accrued expenses and other liabilities	(17,598)	(6,890)
Income taxes payable	1,166	2,229
Net cash provided by operating activities	189,281	109,794
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility development and expansions	(21,872)	(74,858)
Expenditures for other capital improvements	(15,926)	(15,004)
Proceeds from sale of assets	198	48
Increase in other assets	(1,239)	(967)
Payments received on direct financing lease	672	596
Net cash used in investing activities	(38,167)	(90,185)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	80,623	41,834
Principal repayments of debt	(133,589)	(5,000)
Income tax benefit of equity compensation	1,811	2,239
Purchase and retirement of common stock	(72,589)	(86,580)
Proceeds from exercise of stock options	1,744	4,730
Net cash used in financing activities	(122,000)	(42,777)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	29,114	(23,168)
CASH AND CASH EQUIVALENTS, beginning of period	25,509	45,908
CASH AND CASH EQUIVALENTS, end of period	54,623	22,740
Cash paid during the period for:
Interest (net of amounts capitalized of $384 and $2,792 in 2011 and 2010, respectively)	35,901	33,555
Income taxes	$ 41,461	$ 26,987