CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 181,092	$ 31,680
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	27,630	28,387
Expenses associated with debt refinancing transactions	225	1,541
Amortization of debt issuance costs and other non-cash interest	1,047	1,153
Deferred income taxes	(142,862)	(613)
Income tax benefit of equity compensation	(23)	(2,076)
Non-cash equity compensation	3,214	2,639
Other expenses and non-cash items	97	182
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	28,578	20,276
Accounts payable, accrued expenses and other liabilities	(4,416)	(29,645)
Income taxes payable	2,273	14,783
Net cash provided by operating activities	96,855	68,307
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility development and expansions	(4,182)	(9,406)
Expenditures for other capital improvements	(7,216)	(13,458)
Proceeds from sale of assets	44	441
Increase in other assets	(723)	(830)
Payments received on direct financing lease	422	374
Net cash used in investing activities	(11,655)	(22,879)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	10,000	618,500
Principal repayments of debt	(105,000)	(683,500)
Payment of debt issuance and other refinancing and related costs	(2,415)	(6,292)
Dividends paid	(172)
Income tax benefit of equity compensation	23	2,076
Purchase and retirement of common stock	(5,430)	(2,391)
Proceeds from exercise of stock options	15,227	1,701
Net cash used in financing activities	(87,767)	(69,906)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(2,567)	(24,478)
CASH AND CASH EQUIVALENTS, beginning of period	62,897	55,832
CASH AND CASH EQUIVALENTS, end of period	60,330	31,354
Cash paid during the period for:
Interest (net of amounts capitalized of $141 and $497 in 2013 and 2012, respectively)	2,801	16,052
Income taxes paid	$ 199	$ 1,198