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	$ 17,978	$ 41,366
Depreciation and amortization	25,147	26,521
Amortization of debt issuance costs, discounts and premiums	1,333	1,349
Stock-based compensation expense	3,752	5,360
Impairment of fixed assets	23	0
Net gain on disposition of assets	(9)	(322)
Net change in deferred income taxes	4,987	1,157
Net change in deferred compensation liability	0	204
Changes in operating assets and liabilities:
Accounts receivable, net	(618)	116
Income tax refunds receivable	6,213	1,332
Inventories	156	304
Prepaid expenses	(1,788)	(3,968)
Accounts payable	(5,661)	(15,873)
Income taxes payable	3,969	0
Accrued liabilities	20,138	14,425
Net cash provided by operating activities	75,620	71,971
Cash Flows from Investing Activities:
Capital expenditures	(46,788)	(30,982)
Increase (decrease) in construction contracts payable	11,331	(2,148)
Proceeds from sale of assets	43	324
Decrease in restricted cash	164	0
Increase in deposits and other non-current assets	(117)	(414)
Net cash used in investing activities	(35,367)	(33,220)
Cash Flows from Financing Activities:
Proceeds from issuance of long-term debt and other borrowings	8,000	18,000
Principal payments of debt	(10,805)	(47,751)
Debt issuance and amendment costs	(20)	(4)
Cash dividends paid	(4,131)	(4,111)
Proceeds from stock option exercises	2,103	2,346
Purchases of treasury stock	(18)	(221)
Net cash used in financing activities	(4,871)	(31,741)
Net Increase in Cash and Cash Equivalents	35,382	7,010
Cash and Cash Equivalents - Beginning of Period	89,392	85,719
Cash and Cash Equivalents - End of Period	124,774	92,729
Supplemental Cash Flow Disclosures:
Cash paid for interest, net of amounts capitalized	13,079	10,801
Cash received for federal and state income taxes	$ (3,689)	$ (587)