Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income, before tax amount	$ 5,350	$ 4,448	$ 10,254	$ 10,907
Income tax expense	1,906	1,624	3,618	3,878
Net income	3,444	2,824	6,636	7,029
Investment securities available for sale:
Unrealized holding gains on securities arising during the period, before tax	409	284	265	436
Unrealized holding gains on securities arising during the period, tax	163	109	105	164
Unrealized holding gains on securities arising during the period, net	246	175	160	272
Less: reclassification adjustment for gains on securities included in net income, before tax	16	81	16	175
Less: reclassification adjustment for gains on securities included in net income, tax	5	28	5	61
Less: reclassification adjustment for gains on securities included in net income, net	11	53	11	114
Total unrealized gains on securities available for sale, before tax	393	203	249	261
Total unrealized gains on securities available for sale, tax	158	81	100	103
Total unrealized gains on securities available for sale, net of tax	235	122	149	158
Adjustments related to defined benefit plan:
Amortization of prior service cost, before tax	21	21	42	41
Amortization of prior service cost, tax	8	7	17	7
Amortization of prior service cost, net of tax	13	14	25	34
Total adjustments related to defined benefit plan, before tax	21	21	42	41
Total adjustments related to defined benefit plan, tax	8	7	17	7
Total adjustments related to defined benefit plan, net	13	14	25	34
Net unrealized (losses) from cash flow hedges:
Unrealized holding losses on cash flow hedges arising during the period, before tax	(312)	(366)	(231)	(858)
Unrealized holding losses on cash flow hedges arising during the period, tax	(128)	(138)	(95)	(340)
Unrealized holding losses on cash flow hedges arising during the period, net of tax	(184)	(228)	(136)	(518)
Total unrealized losses on cash flow hedges, before tax	(312)	(366)	(231)	(858)
Total unrealized losses on cash flow hedges, tax	(128)	(138)	(95)	(340)
Total unrealized losses on cash flow hedges, net of tax	(184)	(228)	(136)	(518)
Total other comprehensive income (loss), before tax	102	(142)	60	(556)
Total other comprehensive income (loss), tax	38	(50)	22	(230)
Total other comprehensive income (loss), net	64	(92)	38	(326)
Total comprehensive income, before tax	5,452	4,306	10,314	10,351
Total comprehensive income, tax	1,944	1,574	3,640	3,648
Total comprehensive income	$ 3,508	$ 2,732	$ 6,674	$ 6,703