UNAUDITED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Service revenues	$ 673,872	$ 485,728	$ 1,346,494	$ 1,020,039
Product revenues	186,656	37,390	376,197	75,101
Total revenues	860,528	523,118	1,722,691	1,095,140
Cost of revenues (exclusive of items shown separately below)
Service revenues	455,603	338,291	923,975	707,416
Product revenues	158,723	29,332	326,375	60,522
Total cost of revenues	614,326	367,623	1,250,350	767,938
Selling, general and administrative expenses	122,612	66,794	251,082	137,553
Accretion of environmental liabilities	2,879	2,505	5,714	4,921
Depreciation and amortization	67,468	38,663	127,474	75,494
Income from operations	53,243	47,533	88,071	109,234
Other income (expense)	1,655	(75)	2,180	(374)
Interest expense, net of interest income of $155 and $266 for the quarter and year-to-date ended 2013 and $215 and $402 for the quarter and year-to-date ended 2012, respectively	(19,585)	(10,968)	(39,458)	(22,240)
Income before provision for income taxes	35,313	36,490	50,793	86,620
Provision for income taxes	12,411	13,064	17,389	31,179
Net income	$ 22,902	$ 23,426	$ 33,404	$ 55,441
Earnings per share:
Basic	$ 0.38	$ 0.44	$ 0.55	$ 1.04
Diluted	$ 0.38	$ 0.44	$ 0.55	$ 1.04
Weighted average common shares outstanding - basic	60,550	53,308	60,507	53,268
Weighted average common shares outstanding - diluted	60,687	53,505	60,658	53,497