Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net periodic benefit:
Interest cost	$ 187	$ 206
Expected return on plan assets	(290)	(257)
Amortization of net actuarial loss	22	28
Net periodic benefit	(81)	$ (23)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	100
Anticipated contributions to Retirement Plan	$ 500