Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plan
Pension and Other Postretirement Benefit Contributions
Pension contribution made	$ 1,000
Pension Plan | Minimum
Pension and Other Postretirement Benefit Contributions
Requisite service period for receiving benefits under the plan			1 year
Supplemental Employee Retirement Plan (SERP)
Net periodic benefit cost for the year:
Service cost	20	$ 10	$ 40	$ 20
Interest cost	38	35	75	70
Net periodic benefit cost	$ 58	$ 45	$ 115	$ 90