UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Total revenues	$ 1,552,719	$ 1,397,900	$ 2,929,414	$ 2,705,287
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	1,035,542	947,512	2,006,612	1,879,026
Selling, general and administrative expenses	197,876	167,382	379,744	334,135
Accretion of environmental liabilities	3,304	3,486	6,521	6,893
Depreciation and amortization	100,504	89,697	195,569	174,455
Income from operations	215,493	189,823	340,968	310,778
Other expense, net	(167)	(1,283)	(1,308)	(1,167)
Loss on early extinguishment of debt	0	0	0	(2,362)
Interest expense, net of interest income of $4,352, $2,001, $7,866, and $4,956, respectively	(36,449)	(30,072)	(64,988)	(50,704)
Income before provision for income taxes	178,877	158,468	274,672	256,545
Provision for income taxes	45,597	42,702	71,560	68,378
Net income	$ 133,280	$ 115,766	$ 203,112	$ 188,167
Earnings per share:
Basic (in dollars per share)	$ 2.47	$ 2.14	$ 3.77	$ 3.48
Diluted (in dollars per share)	$ 2.46	$ 2.13	$ 3.75	$ 3.46
Shares used to compute earnings per share - Basic (in shares)	53,932	54,092	53,931	54,084
Shares used to compute earnings per share - Diluted (in shares)	54,248	54,448	54,231	54,422
Service revenues
Revenues:
Total revenues	$ 1,288,370	$ 1,159,090	$ 2,440,228	$ 2,212,323
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	850,391	771,600	1,666,740	1,523,195
Product revenues
Revenues:
Total revenues	264,349	238,810	489,186	492,964
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues	$ 185,151	$ 175,912	$ 339,872	$ 355,831