Comprehensive Income Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Schedule of Comprehensive Income [Line Items]
Other comprehensive income, before reclassifications, net of tax	[1]	$ 2,437	$ 745
Reclassification from Accumulated Other Comprehensive Income, net of tax	[1]	99	165
Other Comprehensive Income, before Tax		4,173	1,494
Other Comprehensive Income, Tax		(1,637)	(584)
Other Comprehensive Income	[1]	2,536	910
Unrealized Gains and Losses on Available for Sale Securities [Member]
Schedule of Comprehensive Income [Line Items]
Other Comprehensive Income Loss Before Reclassifications Before Tax		4,010	1,225
Other Comprehensive Income Loss Before Reclassifications Tax (Expense) Benefit		(1,573)	(480)
Other comprehensive income, before reclassifications, net of tax		2,437	745
Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax			90
Reclassification From Accumulated Other Comprehensive Income Current Period Tax (Expense) Benefit			(35)
Reclassification from Accumulated Other Comprehensive Income, net of tax		0	55
Other Comprehensive Income	[1]	2,437	800
Amortization of Net Retirement Plan Actuarial Loss [Member]
Schedule of Comprehensive Income [Line Items]
Other comprehensive income, before reclassifications, net of tax	[1]	0	0
Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax		166	192
Reclassification From Accumulated Other Comprehensive Income Current Period Tax (Expense) Benefit		(65)	(75)
Reclassification from Accumulated Other Comprehensive Income, net of tax		101	117
Other Comprehensive Income	[1]	101	117
Accretion of Net Retirement Plan Prior Service Credit [Member]
Schedule of Comprehensive Income [Line Items]
Other comprehensive income, before reclassifications, net of tax	[1]	0	0
Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax		(3)	(13)
Reclassification From Accumulated Other Comprehensive Income Current Period Tax (Expense) Benefit		1	6
Reclassification from Accumulated Other Comprehensive Income, net of tax		(2)	(7)
Other Comprehensive Income	[1]	$ (2)	$ (7)

[1] All amounts are net of tax. Amounts in parentheses indicate debits.