CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues	$ 523,118	$ 447,235	$ 1,095,140	$ 882,197
Cost of revenues (exclusive of items shown separately below)	367,623	307,754	767,938	620,331
Selling, general and administrative expenses	66,794	58,254	137,553	113,048
Accretion of environmental liabilities	2,505	2,407	4,921	4,796
Depreciation and amortization	38,663	26,936	75,494	52,396
Income from operations	47,533	51,884	109,234	91,626
Other (expense) income	(75)	2,868	(374)	5,767
Interest expense, net of interest income of $215 and $402, for the quarter and year-to-date ended 2012 and $302 and $546 for the quarter and year-to-date ended 2011, respectively	(10,968)	(10,642)	(22,240)	(17,120)
Income from continuing operations, before provision for income taxes	36,490	44,110	86,620	80,273
Provision for income taxes	13,064	14,954	31,179	28,387
Net Income	$ 23,426	$ 29,156	$ 55,441	$ 51,886
Earnings per share:
Basic	$ 0.44	$ 0.55	$ 1.04	$ 0.98
Diluted	$ 0.44	$ 0.55	$ 1.04	$ 0.97
Weighted average common shares outstanding	53,308	52,939	53,268	52,869
Weighted average common shares outstanding plus potentially dilutive common shares	53,505	53,362	53,497	53,261