Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 51,738	$ 181,092
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	28,384	27,630
Expenses associated with debt refinancing transactions		225
Amortization of debt issuance costs and other non-cash interest	771	1,047
Deferred income taxes	(995)	(142,862)
Non-cash revenue	(496)
Income tax benefit of equity compensation	(103)	(23)
Non-cash equity compensation	3,293	3,214
Other expenses and non-cash items	2,316	97
Changes in assets and liabilities, net:
Accounts receivable, prepaid expenses and other assets	7,610	28,578
Accounts payable, accrued expenses and other liabilities	(26,655)	(4,416)
Income taxes payable	719	2,273
Net cash provided by operating activities	66,582	96,855
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for facility development and expansions	(18,507)	(4,182)
Expenditures for other capital improvements	(8,573)	(7,216)
Proceeds from sale of assets	192	44
Increase in other assets	(314)	(723)
Payments received on direct financing lease	476	422
Net cash used in investing activities	(26,726)	(11,655)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	35,000	10,000
Principal repayments of debt	(45,000)	(105,000)
Payment of debt issuance and other refinancing and related costs		(2,415)
Dividends paid	(56,267)	(172)
Income tax benefit of equity compensation	103	23
Purchase and retirement of common stock	(2,768)	(5,430)
Proceeds from exercise of stock options	3,838	15,227
Net cash used in financing activities	(65,094)	(87,767)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(25,238)	(2,567)
CASH AND CASH EQUIVALENTS, beginning of period	77,919	62,897
CASH AND CASH EQUIVALENTS, end of period	52,681	60,330
Cash paid during the period for:
Interest (net of amounts capitalized of $435 and $141 in 2014 and 2013, respectively)	2,476	2,801
Income taxes paid	$ 224	$ 199