Schedule of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Change in net unrealized Gain during period:
Change in net unrealized gain during period, before tax amount	$ 10,043	$ (9,196)	$ 18,671	$ 1,412
Change in net unrealized gain during period, tax expense (benefit)	3,947	(3,618)	7,322	555
Change in net unrealized gain during period, net of tax amount	6,096	(5,578)	11,349	857
Reclassification adjustment for gains included in net income:
Reclassification adjustment for gains included in net income, before tax amount	(108)	(46)	(87)	(52)
Reclassification adjustment for gains included in net income, tax expense (benefit)	(42)	(18)	(34)	(20)
Reclassification adjustment for gains included in net income, net of tax amount	(66)	(28)	(53)	(32)
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	452	451	904	902
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax	170	177	340	355
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	282	274	564	547
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(804)	0	(3,002)	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(305)	0	(1,141)	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(499)	0	(1,861)	0
Change in net actuarial loss:
Change in net actuarial loss, before tax amount	13	13	28	28
Change in net actuarial loss, tax expense (benefit)	5	5	11	11
Change in net actuarial loss, net of tax amount	8	8	17	17
Other comprehensive income (loss):
Other comprehensive income (loss), before tax	9,596	(8,778)	16,514	2,290
Total other comprehensive income, tax expense (benefit)	3,775	(3,454)	6,498	901
Total other comprehensive income, net of tax amount	$ 5,821	$ (5,324)	$ 10,016	$ 1,389