Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Accumulated other comprehensive income, beginning balance			$ (1,895)	$ 4,025
Period change, net of tax	(61)	(524)	(202)	2,943
Accumulated other comprehensive income, ending balance	(2,097)	6,968	(2,097)	6,968
Net Unrealized Gains on AFS Securities [Member]
Accumulated other comprehensive income, beginning balance			13,143	11,936
Period change, net of tax			(814)	3,223
Accumulated other comprehensive income, ending balance	12,329	15,159	12,329	15,159
Noncredit-related Impairment [Member]
Accumulated other comprehensive income, beginning balance			(2,062)	(2,150)
Period change, net of tax			80	88
Accumulated other comprehensive income, ending balance	(1,982)	(2,062)	(1,982)	(2,062)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income, beginning balance			(1,127)	(671)
Period change, net of tax			5	(549)
Accumulated other comprehensive income, ending balance	(1,122)	(1,220)	(1,122)	(1,220)
Pension Benefit Adjustment [Member]
Accumulated other comprehensive income, beginning balance			(11,849)	(5,090)
Period change, net of tax			527	181
Accumulated other comprehensive income, ending balance	$ (11,322)	$ (4,909)	$ (11,322)	$ (4,909)