Pension Plans And Other Postretirement Benefit Plans (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax	$ (7,568)	$ (6,650)
Pension Plan And SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax	7,321	6,527
Service cost	18,302	19,791	$ 15,757
Interest cost	27,544	26,117	26,224
Expected return on plan assets	(27,547)	(28,299)	(32,131)
Amortization of prior service cost	2	2	22
Net loss recognition	8,511	9,451	4,731
Net periodic benefit cost	26,812	27,062	14,603
Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax	247	123
Service cost	3,205	2,925	1,844
Interest cost	6,110	5,158	5,226
Expected return on plan assets	(1,861)	(1,991)	(1,903)
Amortization of prior service cost	(1,208)	(1,199)	(1,116)
Net loss recognition	5,728	5,095	4,289
Net periodic benefit cost	$ 11,974	$ 9,988	$ 8,340