Retirement Plans (Schedule Of Net Periodic Benefit Cost (Credit) For Pension And Postretirement Plans) (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, Contributions by Employer	$ 4,000
Settlement loss - net periodic benefit cost (credit)	2,235	$ 0	$ 0
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	9,988
Net gain (loss) in AOCI expected to be recognized in next year	(4,866)
Defined Benefit Plan, Benefit Obligation	165,129	173,208	185,944
Service cost	0	0	0
Interest cost	6,995	7,094	7,468
Expected return on plan assets	(11,397)	(12,360)	(13,305)
Defined Benefit Plan, Amortization of Gains (Losses)	6,149	5,926	2,895
Defined Benefit Plan, Actuarial Net (Gains) Losses	(2,097)	(8,085)
Defined Benefit Plan, Fair Value of Plan Assets	161,667	157,318	170,199
Defined Benefit Plan, Actual Return on Plan Assets	13,326	(1,136)
Defined Benefit Plan, Contributions by Employer	4,000	0
Defined Benefit Plan, Benefits Paid	(12,977)	(11,745)
Defined Benefit Plan, Funded Status of Plan	(3,462)	(15,890)
Defined Benefit Plan, Net Periodic Benefit Cost	3,982	660	(2,942)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	3,462	15,890
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(47,658)	(60,067)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(47,658)	(60,067)
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	10,051
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	9,821
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	10,181
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	10,268
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	50,166
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	1,911
Net gain (loss) in AOCI expected to be recognized in next year	(123)
Defined Benefit Plan, Benefit Obligation	9,720	9,994	10,595
Service cost	0	0	0
Interest cost	402	403	454
Defined Benefit Plan, Amortization of Gains (Losses)	117	123	19
Amortization of prior service cost (credit)	0	0	50
Defined Benefit Plan, Actuarial Net (Gains) Losses	110	(226)
Defined Benefit Plan, Fair Value of Plan Assets	0	0	0
Defined Benefit Plan, Actual Return on Plan Assets	0	0
Defined Benefit Plan, Contributions by Employer	786	778
Defined Benefit Plan, Benefits Paid	(786)	(778)
Defined Benefit Plan, Funded Status of Plan	(9,720)	(9,994)
Settlement loss - net periodic benefit cost (credit)	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	519	526	523
Pension and Other Postretirement Defined Benefit Plans, Liabilities	9,720	9,994
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(2,281)	(2,288)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(2,281)	(2,288)
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	855
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	882
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	834
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	766
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	3,309
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	94
Net gain (loss) in AOCI expected to be recognized in next year	52
Defined Benefit Plan, Benefit Obligation	939	954	1,067
Service cost	21	33	31
Interest cost	38	40	47
Defined Benefit Plan, Amortization of Gains (Losses)	(67)	(53)	(71)
Amortization of prior service cost (credit)	0	0	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	7	(121)
Defined Benefit Plan, Fair Value of Plan Assets	0	0	0
Defined Benefit Plan, Actual Return on Plan Assets	0	0
Defined Benefit Plan, Contributions by Employer	81	65
Defined Benefit Plan, Benefits Paid	(81)	(65)
Defined Benefit Plan, Funded Status of Plan	(939)	(954)
Defined Benefit Plan, Net Periodic Benefit Cost	(8)	20	$ 7
Pension and Other Postretirement Defined Benefit Plans, Liabilities	939	954
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	258	332
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	258	$ 332
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	99
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	100
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	103
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	98
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	$ 419