Other Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Accumulated other comprehensive income, beginning balance			$ (1,895)	$ 4,025
Period change, net of tax	(638)	3,106	(141)	3,467
Accumulated other comprehensive income, ending balance	(2,036)	7,492	(2,036)	7,492
Net Unrealized Gains on AFS Securities [Member]
Accumulated other comprehensive income, beginning balance			13,143	11,936
Period change, net of tax			(596)	3,534
Accumulated other comprehensive income, ending balance	12,547	15,470	12,547	15,470
Noncredit-related Impairment [Member]
Accumulated other comprehensive income, beginning balance			(2,062)	(2,150)
Period change, net of tax			80	(13)
Accumulated other comprehensive income, ending balance	(1,982)	(2,163)	(1,982)	(2,163)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income, beginning balance			(1,127)	(671)
Period change, net of tax			19	(174)
Accumulated other comprehensive income, ending balance	(1,108)	(845)	(1,108)	(845)
Pension Benefit Adjustment [Member]
Accumulated other comprehensive income, beginning balance			(11,849)	(5,090)
Period change, net of tax			356	120
Accumulated other comprehensive income, ending balance	$ (11,493)	$ (4,970)	$ (11,493)	$ (4,970)