Schedule of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Change in net unrealized Gain during period:
Change in net unrealized gain during period, before tax amount	$ (3,430)	$ 10,855	$ 15,241	$ 12,264
Change in net unrealized gain during period, tax expense (benefit)	(1,359)	4,272	5,963	4,827
Change in net unrealized gain during period, net of tax amount	(2,071)	6,583	9,278	7,437
Reclassification adjustment for gains included in net income:
Reclassification adjustment for gains included in net income, before tax amount	(225)	(23)	(312)	(75)
Reclassification adjustment for gains included in net income, tax expense (benefit)	(89)	(10)	(123)	(30)
Reclassification adjustment for gains included in net income, net of tax amount	(136)	(13)	(189)	(45)
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	490	448	1,394	1,353
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax	209	177	549	532
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	281	271	845	821
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	512	(436)	(2,490)	(436)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	195	(172)	(946)	(172)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	317	(264)	(1,544)	(264)
Change in net actuarial loss:
Change in net actuarial loss, before tax amount	15	15	43	43
Change in net actuarial loss, tax expense (benefit)	6	6	17	17
Change in net actuarial loss, net of tax amount	9	9	26	26
Other comprehensive income (loss):
Other comprehensive income (loss), before tax	(2,638)	10,859	13,876	13,149
Total other comprehensive income, tax expense (benefit)	(1,038)	4,273	5,460	5,174
Total other comprehensive income, net of tax amount	$ (1,600)	$ 6,586	$ 8,416	$ 7,975