UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Total revenues	$ 1,169,109	$ 808,148
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	843,389	560,536
Selling, general and administrative expenses	151,173	121,641
Accretion of environmental liabilities	3,156	2,953
Depreciation and amortization	84,298	72,163
Income from operations	87,093	50,855
Other income (expense), net	704	(1,228)
Interest expense, net of interest income of $493 and $479, respectively	(25,017)	(17,918)
Income before provision for income taxes	62,780	31,709
Provision for income taxes	17,466	9,973
Net income	$ 45,314	$ 21,736
Earnings per share:
Basic (in dollars per share)	$ 0.83	$ 0.40
Diluted (in dollars per share)	$ 0.83	$ 0.39
Shares used to compute earnings per share - Basic (in shares)	54,408	54,723
Shares used to compute earnings per share - Diluted (in shares)	54,672	55,043
Service revenues
Revenues:
Total revenues	$ 942,061	$ 662,708
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	693,424	450,338
Product revenues
Revenues:
Total revenues	227,048	145,440
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	$ 149,965	$ 110,198