Schedule of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Change in net unrealized Gain during period:
Change in net unrealized gain during period, before tax amount	$ 10,855	$ (3,773)	$ 12,264	$ 12,942
Change in net unrealized gain during period, tax expense (benefit)	4,272	(1,581)	4,827	4,900
Change in net unrealized gain during period, net of tax amount	6,583	(2,192)	7,437	8,042
Reclassification adjustment for gains included in net income:
Reclassification adjustment for gains included in net income, before tax amount	(23)	8	(75)	(80)
Reclassification adjustment for gains included in net income, tax expense (benefit)	(10)	3	(30)	(32)
Reclassification adjustment for gains included in net income, net of tax amount	(13)	5	(45)	(48)
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	448	451	1,353	902
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax	177	274	532	547
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	271	177	821	355
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(436)	0	(436)	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(172)	0	(172)	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(264)	0	(264)	0
Change in net actuarial loss:
Change in net actuarial loss, before tax amount	15	33	43	103
Change in net actuarial loss, tax expense (benefit)	6	13	17	41
Change in net actuarial loss, net of tax amount	9	20	26	62
Other comprehensive income (loss):
Other comprehensive income (loss), before tax	10,859	(3,281)	13,149	13,867
Total other comprehensive income, tax expense (benefit)	4,273	(1,291)	5,174	5,456
Total other comprehensive income, net of tax amount	$ 6,586	$ (1,990)	$ 7,975	$ 8,411