Supplemental Balance Sheet and Income Statement Information - Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Changes in accumulated other comprehensive income (loss)
Beginning balance			$ 368,956
Other comprehensive income (loss), net of tax	$ 650	$ (658)	748	$ 678
Ending balance	402,650		402,650
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Beginning balance			(11,038)	(10,634)
Other comprehensive income (loss) before reclassifications			668	598
Amounts reclassified from accumulated other comprehensive income (loss)			80	80
Other comprehensive income (loss), net of tax			748	678
Ending balance	(10,290)	(9,956)	(10,290)	(9,956)
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)			80	80
Other comprehensive income (loss), net of tax			80	1,508
Ending balance	(3,687)	(3,848)	(3,687)	(3,848)
Foreign currency items
Changes in accumulated other comprehensive income (loss)
Beginning balance			(7,273)	(5,280)
Other comprehensive income (loss) before reclassifications			668	(830)
Other comprehensive income (loss), net of tax			668	(830)
Ending balance	$ (6,605)	$ (6,110)	$ (6,605)	$ (6,110)