Other Comprehensive Income (Loss) (Component Of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Other Comprehensive Income (Loss) [Abstract]
Changes in pension plan assets and benefit obligations, Net-of-tax amount	$ (27,134)	$ (27,134)	$ (20,542)	$ (20,954)
Unrealized gains on available-for-sale securities, Net-of-tax amount	7,237	9,616	10,471	12,673
Unrealized net holding loss on cash flow hedge, Net-of-tax amount	0	0	(437)	(550)
Total accumulated other comprehensive income (loss), Net-of-tax amount	$ (19,897)	$ (17,518)	$ (10,508)	$ (8,831)