Discontinued operations - Schedule of Income and Expense Constituting Pretax Income (Loss) From Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations, net of tax	$ (39)	$ 49,012	$ (938)	$ 115,370
Everus Corporation | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	0	760,822	2	2,089,446
Operating expenses	52	705,135	1,195	1,944,457
Operating (loss) income	(52)	55,687	(1,193)	144,989
Other income	0	4,868	0	11,044
Interest expense	0	2,128	0	6,431
(Loss) income from discontinued operations before income taxes	(52)	58,427	(1,193)	149,602
Income tax (benefit) expense	(13)	9,415	(255)	34,232
Discontinued operations, net of tax	$ (39)	$ 49,012	$ (938)	$ 115,370