Accumulated Other Comprehensive Loss - Components of and Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income
Balance at beginning of period	$ (11,635)	$ (12,780)
Other comprehensive income before reclassifications	291	577
Amounts reclassified from accumulated other comprehensive loss, net of tax	83	96
Tax	(46)	(100)
Net current period other comprehensive income, net of tax	374	673
Accumulated other comprehensive loss	(11,261)	(12,107)
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	83	96
Net current period other comprehensive income, net of tax	83	96
Accumulated other comprehensive loss	(10,412)	(11,872)
Foreign currency
Accumulated Other Comprehensive Income
Balance at beginning of period	(1,140)	(812)
Other comprehensive income before reclassifications	291	577
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0
Net current period other comprehensive income, net of tax	291	577
Accumulated other comprehensive loss	$ (849)	$ (235)