Retirement Plans (Schedule Of Change In Benefit Obligation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	$ 249,960	$ 266,911
Service cost	10,645	12,824	10,206
Interest cost	12,839	11,400	10,506
Actuarial loss (gain)	66,640	(35,767)
Gross benefits paid	(25,009)	(5,408)
Benefit obligation at end of year	315,075	249,960	266,911
Accumulated benefit obligation at end of year	241,592	200,577
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	1,529	1,746
Service cost	0	0	0
Interest cost	73	70	73
Actuarial loss (gain)	180	(138)
Gross benefits paid	(145)	(149)
Benefit obligation at end of year	1,637	1,529	1,746
Accumulated benefit obligation at end of year	1,637	1,529
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	2,307	2,854
Service cost	0	0	0
Interest cost	110	112	133
Actuarial loss (gain)	(1,065)	(600)
Gross benefits paid	(88)	(59)
Benefit obligation at end of year	1,264	2,307	2,854
Accumulated benefit obligation at end of year	$ 0	$ 0