Accumulated Other Comprehensive Income (Loss) - Components of and Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI, tax	$ (1)	$ (137,000)
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	331,068	303,503
Other comprehensive income (loss) before reclassifications	(182)	137
Amounts reclassified from accumulated other comprehensive income, net of tax	2	349
Net current period other comprehensive income (loss), net of tax	(180)	486
Balance at end of period	341,143	316,452
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	2	349
Net current period other comprehensive income (loss), net of tax	2	349
Balance at end of period	265	709
Foreign currency
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	162	220
Other comprehensive income (loss) before reclassifications	(182)	137
Amounts reclassified from accumulated other comprehensive income, net of tax	0	0
Net current period other comprehensive income (loss), net of tax	(182)	137
Balance at end of period	(20)	357
Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity
Balance at beginning of period	425	580
Other comprehensive income (loss) before reclassifications	(182)
Balance at end of period	$ 245	$ 1,066