Employee Benefit Plans (Details 2) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Pension Benefits
Details of the pre-tax amounts recognized in accumulated other comprehensive loss
Balance at beginning of year, Unamortized Actuarial Net Losses	$ 4,244
Balance at beginning of year, Unamortized Prior Service Costs	0
Amounts arising during the period, Unamortized Actuarial Net Losses	(245)
Amounts arising during the period, Unamortized Prior Service Costs	0
Amounts recognized as a component of net periodic benefit cost, Unamortized Actuarial Net Losses	(252)
Amounts recognized as a component of net periodic benefit cost, Unamortized Prior Service Costs	0
Balance at end of year, Unamortized Actuarial Net Losses	3,747
Balance at end of year, Unamortized Prior Service Costs	0
Postretirement Benefits
Details of the pre-tax amounts recognized in accumulated other comprehensive loss
Balance at beginning of year, Unamortized Actuarial Net Losses	397
Balance at beginning of year, Unamortized Prior Service Costs	0
Amounts arising during the period, Unamortized Actuarial Net Losses	(7,903)
Amounts arising during the period, Unamortized Prior Service Costs	0
Amounts recognized as a component of net periodic benefit cost, Unamortized Actuarial Net Losses	0
Amounts recognized as a component of net periodic benefit cost, Unamortized Prior Service Costs	455
Balance at end of year, Unamortized Actuarial Net Losses	(7,506)
Balance at end of year, Unamortized Prior Service Costs	$ 455