Accumulated Other Comprehensive Income (Loss) - Components of and Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI, tax	$ (2)	$ 3,000
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	361,259	331,068
Other comprehensive income (loss) before reclassifications	(155)	268
Amounts reclassified from accumulated other comprehensive income, net of tax	9	(9)
Net current period other comprehensive income (loss), net of tax	(146)	259
Balance at end of period	391,824	351,543
Unrecognized pension and postretirement benefits
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	55	263
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income, net of tax	9	(9)
Net current period other comprehensive income (loss), net of tax	9	(9)
Balance at end of period	64	254
Foreign currency
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	1,258	162
Other comprehensive income (loss) before reclassifications	(155)	268
Amounts reclassified from accumulated other comprehensive income, net of tax	0	0
Net current period other comprehensive income (loss), net of tax	(155)	268
Balance at end of period	1,103	430
Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	1,313	425
Other comprehensive income (loss) before reclassifications	(155)
Net current period other comprehensive income (loss), net of tax		259
Balance at end of period	$ 1,167	$ 684