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
Net Periodic Pension Cost [Abstract]
Interest cost	$ 106	$ 111	$ 212	$ 222
Amortization of net loss	26	35	53	70
Expected return on plan assets	(174)	(161)	(347)	(323)
Net periodic pension cost	(42)	(15)	(82)	(31)
Contributed amount