Comprehensive Income Other Comprehense 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
Comprehensive Income [Abstract]
Net Unrealized Securities Holding Gains Arising During the Period, Before-Tax Amount	$ 679	$ 1,843	$ 1,256	$ 8,115
Net Unrealized Securities Holding Gain Arising During the Period, Tax (Expense) Benefit	(268)	(730)	(498)	(3,215)
Net Unrealized Securities Holding Gains Arising During the Period	411	1,113	758	4,900
Reclassification Adjustment for Securities Gains Included in Net Income, Before-Tax Amount	(64)	(1,772)	(709)	(2,795)
Reclassification Adjustment for Securities Gains Included in Net Income, Tax (Expense) Benefit	25	702	281	1,107
Reclassification Adjustment for Securities Gains Included in Net Income	(39)	(1,070)	(428)	(1,688)
Amortization of Net Retirement Plan Actuarial Loss, Before-Tax Amount	377	257	1,134	767
Amortization of Net Retirement Plan Actuarial Loss, Tax (Expense) Benefit	(149)	(102)	(449)	(303)
Amortization of Net Retirement Plan Actuarial Loss	228	155	685	464
Accretion of Net Retirement Plan Prior Service Credit, Before-Tax Amount	(7)	(33)	(22)	(94)
Accretion of Net Retirement Plan Prior Service Credit, Tax (Expense) Benefit	3	13	9	36
Accretion of Net Retirement Plan Prior Service Credit	(4)	(20)	(13)	(58)
Other Comprehensive Loss, Before-Tax Amount	985	295	1,659	5,993
Other Comprehensive Loss, Tax (Expense) Benefit	(389)	(117)	(657)	(2,375)
Other Comprehensive Loss, Net-of-Tax Amount	$ 596	$ 178	$ 1,002	$ 3,618