UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Total revenues	$ 1,356,312	$ 926,458	$ 2,525,421	$ 1,734,606
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	898,469	617,886	1,741,858	1,178,422
Selling, general and administrative expenses	155,608	124,106	306,781	245,747
Accretion of environmental liabilities	3,197	2,873	6,353	5,826
Depreciation and amortization	87,868	71,592	172,166	143,755
Income from operations	211,170	110,001	298,263	160,856
Other income (expense), net	1,265	(1,480)	1,969	(2,708)
Gain on sale of business	8,864	0	8,864	0
Interest expense, net of interest income of $563, $580, $1,056 and $1,060, respectively	(26,256)	(18,051)	(51,273)	(35,969)
Income before provision for income taxes	195,043	90,470	257,823	122,179
Provision for income taxes	46,886	23,395	64,352	33,368
Net income	$ 148,157	$ 67,075	$ 193,471	$ 88,811
Earnings per share:
Basic (in dollars per share)	$ 2.73	$ 1.23	$ 3.56	$ 1.63
Diluted (in dollars per share)	$ 2.71	$ 1.22	$ 3.54	$ 1.62
Shares used to compute earnings per share - Basic (in shares)	54,318	54,529	54,362	54,625
Shares used to compute earnings per share - Diluted (in shares)	54,597	54,854	54,639	54,945
Service revenues
Revenues:
Total revenues	$ 1,085,043	$ 734,563	$ 2,027,104	$ 1,397,271
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	736,560	492,662	1,429,984	943,000
Product revenues
Revenues:
Total revenues	271,269	191,895	498,317	337,335
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	$ 161,909	$ 125,224	$ 311,874	$ 235,422