Other Comprehensive Income (Loss) (Component Of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 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	20,428	19,498	10,186
Unrealized gains on available-for-sale securities, Tax expense (benefit)	7,151	6,825	3,565
Unrealized gains on available-for-sale securities, Net-of-tax amount	13,277	12,673	6,621
Unrealized net holding loss on cash flow hedge, Before-tax amount	(448)	(846)	(1,337)
Unrealized net holding loss on cash flow hedge, Tax expense (benefit)	(157)	(296)	(468)
Unrealized net holding loss on cash flow hedge, Net-of-tax amount	(291)	(550)	(869)
Total accumulated other comprehensive income (loss), Before-tax amount	(11,623)	(13,585)	(15,654)
Total accumulated other comprehensive income (loss), Tax expense (benefit)	(4,067)	(4,754)	(5,479)
Total accumulated other comprehensive income (loss), Net-of-tax amount	$ (7,556)	$ (8,831)	$ (10,175)