CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues	$ 556,053	$ 487,651	$ 1,438,250	$ 1,314,186
Cost of revenues (exclusive of items shown separately below)	386,518	335,273	1,006,849	919,970
Selling, general and administrative expenses	65,704	53,619	178,752	149,832
Accretion of environmental liabilities	2,435	2,495	7,231	7,799
Depreciation and amortization	34,604	22,892	87,000	67,671
Income from operations	66,792	73,372	158,418	168,914
Other income (loss)	164	(669)	5,931	2,485
Loss on early extinguishment of debt	0	(2,294)	0	(2,294)
Interest expense, net of interest income of $153 and $700 for the quarter and year-to-date ended 2011 and $297 and $564 for the quarter and year-to-date ended 2010, respectively	(10,927)	(7,198)	(28,047)	(21,772)
Income from continuing operations, before provision for income taxes	56,029	63,211	136,302	147,333
Provision for income taxes	18,896	24,384	47,283	42,941
Income from continuing operations	37,133	38,827	89,019	104,392
Income from discontinued operations, net of tax				2,794
Net income	$ 37,133	$ 38,827	$ 89,019	$ 107,186
Earnings per share:
Basic (in dollars per share)	$ 0.70	$ 0.74	$ 1.68	$ 2.04
Diluted (in dollars per share)	$ 0.70	$ 0.73	$ 1.67	$ 2.03
Weighted average common shares outstanding (in shares)	53,023	52,658	52,921	52,581
Weighted average common shares outstanding plus potentially dilutive common shares (in shares)	53,370	52,963	53,298	52,852