Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012		Dec. 31, 2011
Accumulated other comprehensive income	$ 26,025		$ 166,040		$ 26,025		$ 166,040		$ 136,344		$ 110,538
Other Comprehensive Income Before Reclassifications					(180,109)		86,445
Reclassified from Accumulated Oher Comprehensive Income					2,175		3,075
Other Comprehensive Income (Loss), before Tax					(177,934)		89,520
Other Comprehensive Income (Loss), Tax					67,615		(34,018)
Other Comprehensive Income (Loss), Net of Tax	4,161		29,308		(110,319)		55,502
Unrealized Gain Loss on Securities OTTI [Member]
Accumulated other comprehensive income	4,132	[1]	3,271	[1]	4,132	[1]	3,271	[1]	3,245	[1]	(4,321)	[1]
Other Comprehensive Income Before Reclassifications					170	[1]	11,018	[1]
Reclassified from Accumulated Oher Comprehensive Income					1,260	[1]	1,227	[1]
Other Comprehensive Income (Loss), before Tax					1,430	[1]	12,245	[1]
Other Comprehensive Income (Loss), Tax					(543)	[1]	(4,653)	[1]
Other Comprehensive Income (Loss), Net of Tax					887	[1]	7,592	[1]
Unrealized Gain Loss on Securities Other [Member]
Accumulated other comprehensive income	47,631	[1]	182,689	[1]	47,631	[1]	182,689	[1]	160,263	[1]	136,137	[1]
Other Comprehensive Income Before Reclassifications					(180,279)	[1]	75,427	[1]
Reclassified from Accumulated Oher Comprehensive Income					(1,385)	[1]	(342)	[1]
Other Comprehensive Income (Loss), before Tax					(181,664)	[1]	75,085	[1]
Other Comprehensive Income (Loss), Tax					69,032	[1]	(28,533)	[1]
Other Comprehensive Income (Loss), Net of Tax					(112,632)	[1]	46,552	[1]
Pension Loss [Member]
Accumulated other comprehensive income	(25,738)	[2]	(19,920)	[2]	(25,738)	[2]	(19,920)	[2]	(27,164)	[2]	(21,278)	[2]
Other Comprehensive Income Before Reclassifications					0	[2]	0	[2]
Reclassified from Accumulated Oher Comprehensive Income					2,300	[2]	2,190	[2]
Other Comprehensive Income (Loss), before Tax					2,300	[2]	2,190	[2]
Other Comprehensive Income (Loss), Tax					(874)	[2]	(832)	[2]
Other Comprehensive Income (Loss), Net of Tax					$ 1,426	[2]	$ 1,358	[2]

[1] The pre-tax amounts reclassified from accumulated other comprehensive income are included in "investment securities gains (losses), net" in the consolidated statements of income.

[2] The pre-tax amounts reclassified from accumulated other comprehensive income are included in the computation of net periodic pension cost as "amortization of unrecognized net loss" (see Note 7).