Employee Benefit Plans (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Components of net periodic cost (benefit) for pension and postretirement plans
Service cost	$ 85	$ 88	$ 254	$ 265
Interest cost	210	235	631	706
Expected return on plan assets	(281)	(283)	(843)	(848)
Defined Benefit Plan Amortization Of Actuarial Loss Gain And Prior Service Cost Credit	46	184	137	552
Net periodic cost recognized	$ 60	$ 224	$ 179	$ 675