Other Comprehensive Income (Loss) (Component Of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Other Comprehensive Income (Loss) [Abstract]
Changes in pension plan assets and benefit obligations, Before-tax amount	$ (31,603)	$ (32,237)	$ (24,503)
Changes in pension plan assets and benefit obligations, Tax expense (benefit)	(11,061)	(11,283)	(8,576)
Changes in pension plan assets and benefit obligations, Net-of-tax amount	(20,542)	(20,954)	(15,927)
Unrealized gains on available-for-sale securities, Before-tax amount	21,756	19,498	24,253
Unrealized gains on available-for-sale securities, Tax expense (benefit)	7,615	6,825	8,488
Unrealized gains on available-for-sale securities, Net-of-tax amount	14,141	12,673	15,765
Unrealized net holding loss on cash flow hedge, Before-tax amount	(229)	(846)	(1,099)
Unrealized net holding loss on cash flow hedge, Tax expense (benefit)	(80)	(296)	(385)
Unrealized net holding loss on cash flow hedge, Net-of-tax amount	(149)	(550)	(714)
Total accumulated other comprehensive income (loss), Before-tax amount	(10,076)	(13,585)	(1,349)
Total accumulated other comprehensive income (loss), Tax expense (benefit)	(3,526)	(4,754)	(473)
Total accumulated other comprehensive income (loss), Net-of-tax amount	$ (6,550)	$ (8,831)	$ (876)