Benefit Plans (Schedule Of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Service cost	$ 1,755	$ 1,754	$ 2,078	$ 3,509	$ 4,157
Interest cost	6,454	6,454	7,408	12,908	14,816
Expected return on assets	(10,874)	$ (10,873)	(11,206)	(21,747)	(22,412)
Amortization of prior service cost	1,296		1,217	2,592	2,433
Amortization of actuarial loss	3,474		3,475	6,948	6,950
Net periodic benefit cost	$ 2,105		$ 2,972	$ 4,210	$ 5,944