Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (4,710)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(873)
Ending Balance	(5,531)
Accumulated Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(838)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(873)
Ending Balance	(1,711)
Accumulated Postretirement Transactions [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(3,872)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	52
Ending Balance	(3,820)
Scenario, Previously Reported [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 52