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	$ 41,366	$ 21,846
Depreciation and amortization	26,521	26,444
Amortization of debt issuance costs and debt discounts	1,349	2,165
Stock-based compensation expense	5,360	3,270
Net gain on disposition of assets	(322)	(129)
Net change in deferred income taxes	1,157	13,392
Net change in deferred compensation liability	204	716
Changes in operating assets and liabilities:
Accounts receivable, net	116	769
Income tax refunds receivable	1,332	3,295
Inventories	304	255
Prepaid expenses	(3,968)	(1,004)
Accounts payable	(15,873)	(8,035)
Income taxes payable	0	1,846
Accrued liabilities	14,425	16,796
Net cash provided by operating activities	71,971	81,626
Cash Flows from Investing Activities:
Capital expenditures	(30,982)	(10,868)
Decrease in construction contracts payable	(2,148)	(94)
Proceeds from sale of assets	324	281
Increase in deposits and other non-current assets	(414)	(1,392)
Net cash used in investing activities	(33,220)	(12,073)
Cash Flows from Financing Activities:
Proceeds from issuance of long-term debt and other borrowings	18,000	0
Principal payments of debt	(47,751)	(45,003)
Debt issuance and amendment costs	(4)	(1,300)
Cash dividends paid	(4,111)	(6,126)
Proceeds from stock option exercises and restricted share issuances	2,346	523
Purchases of treasury stock	(221)	(78)
Net cash used in financing activities	(31,741)	(51,984)
Net Increase in Cash and Cash Equivalents	7,010	17,569
Cash and Cash Equivalents - Beginning of Period	85,719	71,186
Cash and Cash Equivalents - End of Period	92,729	88,755
Supplemental Cash Flow Disclosures:
Cash paid for interest, net of amounts capitalized	10,801	8,323
Cash received for federal and state income taxes	$ (587)	$ (2,140)