Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (6,331)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	129
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	108
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(936)
Ending Balance	(7,030)
Accumulated Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(2,015)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	129
Ending Balance	(1,886)
Accumulated Postretirement Transactions [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(4,731)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	108
Ending Balance	(4,623)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	415
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(936)
Ending Balance	$ (521)