Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (6,331)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	581
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(1,186)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	1,018
Ending Balance	(5,702)
Accumulated Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(2,015)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	581
Ending Balance	(1,434)
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	216
Ending Balance	(4,515)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	415
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(1,186)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	1,018
Ending Balance	247
Scenario, Previously Reported [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 216