Components of Net Periodic Pension Cost (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Average daily balance during the year
Service cost
Interest cost	107	120	214	239
Expected return on plan assets	(192)	(160)	(383)	(320)
Net amortization	92	103	183	206
Net periodic pension cost	7	$ 63	$ 14	$ 125
Defined Benefit Plan, Contributions by Employer	$ 2,000