Accumulated other comprehensive loss - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 3,004,714
Beginning balance	3,004,714	$ 2,704,872
Amounts reclassified from AOCL	1,023	1,111
Other comprehensive income, net of tax	1,023	1,111
Ending balance	3,038,870	2,797,889
Ending Balance	3,038,870
Total
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(106,644)	(119,610)
Beginning balance	(106,644)	(119,610)
Amounts reclassified from AOCL	1,023	1,111
Other comprehensive income, net of tax	1,023	1,111
Ending balance	(105,621)	(118,499)
Ending Balance	(105,621)	(118,499)
Retirement Plans
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(107,176)	(120,142)
Amounts reclassified from AOCL	1,023	1,111
Other comprehensive income, net of tax	1,023	1,111
Ending balance	(106,153)	(119,031)
Foreign Currency
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	532	532
Amounts reclassified from AOCL
Other comprehensive income, net of tax
Ending Balance	$ 532	$ 532