Net Periodic Pension Cost (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Periodic Pension Cost [Abstract]
Interest cost	$ 106	$ 111
Amortization of net loss	26	35
Expected return on plan assets	(173)	(162)
Net periodic pension cost	(41)	(16)
Contributed amount