Other Employee Benefit Plans (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service costs	$ 0	$ 0	$ 156
Interest costs	386	397	353
Net amortization and deferral	235	260	513
Net periodic pension costs	621	$ 657	$ 1,022
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Net loss	$ 52