Supplemental Balance Sheet and Income Statement Information - Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Changes in accumulated other comprehensive income (loss)
Beginning balance			$ 368,956
Other comprehensive income (loss), net of tax	$ (132)	$ (1,611)	616	$ (933)
Ending balance	348,234		348,234
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Beginning balance			(11,038)	(10,634)
Other comprehensive income (loss) before reclassifications			496	(1,053)
Amounts reclassified from accumulated other comprehensive income (loss)			120	120
Other comprehensive income (loss), net of tax			616	(933)
Ending balance	(10,422)	(11,567)	(10,422)	(11,567)
Gains (losses) on cash flow hedges
Changes in accumulated other comprehensive income (loss)
Beginning balance			2	2
Ending balance	2	2	2	2
Defined benefit pension plan items
Changes in accumulated other comprehensive income (loss)
Beginning balance			(3,767)	(5,356)
Other comprehensive income (loss) before reclassifications				1,428
Amounts reclassified from accumulated other comprehensive income (loss)			120	120
Other comprehensive income (loss), net of tax			120	1,548
Ending balance	(3,647)	(3,808)	(3,647)	(3,808)
Foreign currency items
Changes in accumulated other comprehensive income (loss)
Beginning balance			(7,273)	(5,280)
Other comprehensive income (loss) before reclassifications			496	(2,481)
Other comprehensive income (loss), net of tax			496	(2,481)
Ending balance	$ (6,777)	$ (7,761)	$ (6,777)	$ (7,761)