UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues:
Service revenues	$ 594,225	$ 760,667	$ 1,709,018	$ 2,158,344
Product revenues	135,295	132,699	354,095	403,749
Total revenues	729,520	893,366	2,063,113	2,562,093
Cost of revenues (exclusive of items shown separately below)
Service revenues	385,542	523,676	1,148,212	1,484,936
Product revenues	106,373	110,970	287,984	348,905
Total cost of revenues	491,915	634,646	1,436,196	1,833,841
Selling, general and administrative expenses	110,954	93,113	322,501	321,246
Accretion of environmental liabilities	2,476	2,577	7,529	7,795
Depreciation and amortization	73,360	69,060	215,655	205,189
Goodwill impairment charge	34,013	0	34,013	31,992
Income (loss) from operations	16,802	93,970	47,219	162,030
Other expense	(198)	(139)	(737)	(390)
Gain on sale of business	16,431	0	16,431	0
Interest expense, net of interest income of $196, $126, $571 and $465, respectively	(21,565)	(19,017)	(62,192)	(57,704)
(Loss) income before (benefit) provision for income taxes	11,470	74,814	721	103,936
Provision for income taxes	21,725	34,586	27,881	60,402
Net (loss) income	$ (10,255)	$ 40,228	$ (27,160)	$ 43,534
(Loss) earnings per share:
Basic (in USD per share)	$ (0.18)	$ 0.69	$ (0.47)	$ 0.74
Diluted (in USD per share)	$ (0.18)	$ 0.69	$ (0.47)	$ 0.74
Shares used to compute (loss) earnings per share - Basic (in shares)	57,487	58,161	57,575	58,799
Shares used to compute (loss) earnings per share - Diluted (in shares)	57,487	58,268	57,575	58,898