Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Accumulated other comprehensive income, beginning balance	$ (10,499)		$ (1,895)
Other Comprehensive Income Before Reclassifcations	(1,055)
Amounts Reclassified From Accumulated Other Comprehensive Income	2,236
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1,181		497
Accumulated other comprehensive income, ending balance	(9,318)		(1,398)
Net Unrealized Gains on AFS Securities [Member]
Accumulated other comprehensive income, beginning balance	9,711		13,143
Other Comprehensive Income Before Reclassifcations	(1,053)
Amounts Reclassified From Accumulated Other Comprehensive Income	(393)	[1]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(660)		198
Accumulated other comprehensive income, ending balance	9,051		13,341
Noncredit-related Impairment [Member]
Accumulated other comprehensive income, beginning balance	(1,938)		(2,062)
Other Comprehensive Income Before Reclassifcations	0
Amounts Reclassified From Accumulated Other Comprehensive Income	1,384
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1,384		80
Accumulated other comprehensive income, ending balance	(554)		(1,982)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income, beginning balance	(1,006)		(1,127)
Other Comprehensive Income Before Reclassifcations	(2)
Amounts Reclassified From Accumulated Other Comprehensive Income	122
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	120		35
Accumulated other comprehensive income, ending balance	(886)		(1,092)
Pension Benefit Adjustment [Member]
Accumulated other comprehensive income, beginning balance	(17,266)		(11,849)
Other Comprehensive Income Before Reclassifcations	0
Amounts Reclassified From Accumulated Other Comprehensive Income	(337)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	337		184
Accumulated other comprehensive income, ending balance	$ (16,929)		$ (11,665)

[1] Reported as total other-than-temporary impairment losses on securities in the Consolidated Income Statement.