Accumulated Other Comprehensive Loss - Components of and Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income
Balance at beginning of period	$ (11,635)	$ (12,780)
Other comprehensive income before reclassifications	1,545	229
Amounts reclassified from accumulated other comprehensive loss, net of tax of $(0.1) million	234	756
Amounts reclassified from accumulated other comprehensive loss, tax	(100)	(400)
Net current period other comprehensive income, net of tax	1,779	985
Accumulated other comprehensive (loss) income	(9,856)	(11,795)
Unrecognized pension and postretirement benefits
Accumulated Other Comprehensive Income
Balance at beginning of period	(10,495)	(11,968)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax of $(0.1) million	234	756
Net current period other comprehensive income, net of tax	234	756
Accumulated other comprehensive (loss) income	(10,261)	(11,212)
Foreign currency
Accumulated Other Comprehensive Income
Balance at beginning of period	(1,140)	(812)
Other comprehensive income before reclassifications	1,545	229
Amounts reclassified from accumulated other comprehensive loss, net of tax of $(0.1) million	0	0
Net current period other comprehensive income, net of tax	1,545	229
Accumulated other comprehensive (loss) income	$ 405	$ (583)