Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income, before tax amount	$ 4,633	$ 3,845	$ 15,540	$ 10,414
Income tax expense	1,613	1,294	5,491	3,496
Net income	3,020	2,551	10,049	6,918
Other comprehensive income (loss)
Unrealized holding gains on securities arising during the period, before tax	110	14	546	(125)
Unrealized holding gains on securities arising during the period, tax	43	5	207	(50)
Unrealized holding gains on securities arising during the period, net	67	9	339	(75)
Less: reclassification adjustment for gains on securities included in net income, before tax	11	0	186	28
Less: reclassification adjustment for gains on securities included in net income, tax	2	0	63	10
Less: reclassification adjustment for gains on securities included in net income, net of tax	9	0	123	18
Total unrealized gains on securities available for sale, before tax	99	14	360	(153)
Total unrealized gains on securities available for sale, tax	41	5	144	(60)
Total unrealized gains on securities available for sale, net of tax	58	9	216	(93)
Initial recognition of prior service cost, before tax			0	(830)
Initial recognition of prior service cost, tax			0	(332)
Initial recognition of prior service cost, net of tax			0	(498)
Amortization of prior service cost, before tax	22	21	63	63
Amortization of prior service cost, tax	10	8	17	25
Amortization of prior service cost, net of tax	12	13	46	38
Total adjustments related to defined benefit plan, before tax	22	21	63	(767)
Total adjustments related to defined benefit plan, tax	10	8	17	(307)
Total adjustments related to defined benefit plan, net of tax	12	13	46	(460)
Unrealized holding loss on cash flow hedges arising during the period, before tax	503	0	(355)	0
Unrealized holding loss on cash flow hedges arising during the period, tax	195	0	(145)	0
Unrealized holding loss on cash flow hedges arising during the period, net of tax	308	0	(210)	0
Total unrealized loss on cash flow hedges, before tax	503	0	(355)	0
Total unrealized loss on cash flow hedges, tax	195	0	(145)	0
Total unrealized loss on cash flow hedges, net of tax	308	0	(210)	0
Total other comprehensive income, before tax	624	35	68	(920)
Total other comprehensive income, tax	246	13	16	(367)
Total other comprehensive income, net	378	22	52	(553)
Total comprehensive income, before tax	5,257	3,880	15,608	9,494
Total comprehensive income, tax	1,859	1,307	5,507	3,129
Total comprehensive income	$ 3,398	$ 2,573	$ 10,101	$ 6,365