Employee Benefit Plans (Schedule Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Service cost	$ 1,223	$ 1,277	$ 1,252
Interest cost	2,123	2,078	1,899
Expected return on plan assets	(3,215)	(2,971)	(3,165)
Amortization of net loss	1,475	1,552	1,423
Total	$ 1,606	$ 1,936	$ 1,409