Components of Net Periodic Pension Cost (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Average daily balance during the year
Service cost
Interest cost	107	119
Expected return on plan assets	(191)	(160)
Net amortization	91	103
Net periodic pension cost	7	$ 62
Defined Benefit Plan, Contributions by Employer	$ 2,000