Retirement Plans (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Total recognized in net periodic benefit cost and other comprehensive income	$ 16,652	$ 44,377	$ 2,682
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	10,206	7,303	6,883
Interest cost	10,506	9,693	9,399
Expected return on plan assets	(12,872)	(11,283)	(9,329)
Actuarial loss (gain)	7,395	2,859	3,162
Prior service (credit) cost	0	(38)	(89)
Net periodic benefit cost	15,235	8,534	10,026
Current year actuarial loss (gain)	23,557	46,444	8,145
Recognition of actuarial loss (gain)	(7,395)	(2,859)	(3,162)
Recognition of prior service credit (cost)	0	38	89
Total recognized in other comprehensive income	16,162	43,623	5,072
Total recognized in net periodic benefit cost and other comprehensive income	31,397	52,157	15,098
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	73	80	84
Expected return on plan assets	0	0	0
Actuarial loss (gain)	14	7	2
Prior service (credit) cost	0	0	0
Net periodic benefit cost	87	87	86
Current year actuarial loss (gain)	131	156	102
Recognition of actuarial loss (gain)	(14)	(7)	(2)
Recognition of prior service credit (cost)	0	0	0
Total recognized in other comprehensive income	117	149	100
Total recognized in net periodic benefit cost and other comprehensive income	204	236	186
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	133	164	154
Curtailment loss	0	119	0
Actuarial loss (gain)	(618)	(593)	(660)
Prior service (credit) cost	0	40	560
Net periodic benefit cost	(485)	(270)	54
Current year actuarial loss (gain)	(235)	182	(3,109)
Recognition of actuarial loss (gain)	618	593	660
Recognition of prior service credit (cost)	0	(158)	(40)
Adjustment for actual Medicare Part D reimbursement	(10)	(3)	(10)
Total recognized in other comprehensive income	373	614	(2,499)
Total recognized in net periodic benefit cost and other comprehensive income	$ (112)	$ 344	$ (2,445)