Benefit Plans (Schedule of Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Retirement Benefits [Abstract]
Service cost	$ 52	$ 79	$ 87	$ 112
Interest cost	43	33	71	78
Actuarial gain recognized	(15)	(24)	(30)	(43)
Net periodic benefit cost	$ 80	$ 88	$ 128	$ 147