Other Comprehensive Income (Loss) - After-tax Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ (21,079)	$ (16,507)
Net current period change	(408)	(2,845)
Reclassification adjustments for losses reclassified into income	0	0
Ending Balance	(21,487)	(19,352)
Pension and post-retirement benefits plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(18,575)	(20,781)
Reclassification adjustments for losses reclassified into income	(1,034)	186
Ending Balance	(19,609)	(20,595)
Accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(39,654)	(37,288)
Net current period change	(408)	(2,845)
Reclassification adjustments for losses reclassified into income	(1,034)	186
Ending Balance	$ (41,096)	$ (39,947)