Accumulated Other Comprehensive Income - Components of and Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI, tax	$ (3)	$ 133,000
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	331,068	303,503
Other comprehensive income (loss) before reclassifications	268	(509)
Amounts reclassified from accumulated other comprehensive income, net of tax	(9)	333
Net current period other comprehensive income (loss), net of tax	259	(176)
Balance at end of period	351,543	323,639
Unrecognized pension and postretirement benefits
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	263	360
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income, net of tax	(9)	333
Net current period other comprehensive income (loss), net of tax	(9)	333
Balance at end of period	254	693
Foreign currency
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	162	220
Other comprehensive income (loss) before reclassifications	268	(509)
Amounts reclassified from accumulated other comprehensive income, net of tax	0	0
Net current period other comprehensive income (loss), net of tax	268	(509)
Balance at end of period	430	(289)
Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	425	580
Other comprehensive income (loss) before reclassifications	268
Balance at end of period	$ 684	$ 404