Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, beginning balance	$ (1,895)	$ 4,025	$ 3,337
Period change, net of tax	(8,604)	(5,920)	688
Accumulated other comprehensive income, ending balance	(10,499)	(1,895)	4,025
Net Unrealized Gains on AFS Securities [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, beginning balance	13,143	11,936	11,148
Period change, net of tax	(3,432)	1,207	788
Accumulated other comprehensive income, ending balance	9,711	13,143	11,936
Noncredit-related Impairment [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, beginning balance	(2,062)	(2,150)	(2,261)
Period change, net of tax	124	88	111
Accumulated other comprehensive income, ending balance	(1,938)	(2,062)	(2,150)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, beginning balance	(1,127)	(671)	(8)
Period change, net of tax	121	(456)	(663)
Accumulated other comprehensive income, ending balance	(1,006)	(1,127)	(671)
Pension Benefit Adjustment [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated other comprehensive income, beginning balance	(11,849)	(5,090)	(5,542)
Period change, net of tax	(5,417)	(6,759)	452
Accumulated other comprehensive income, ending balance	$ (17,266)	$ (11,849)	$ (5,090)