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	$ 8,157	$ 6,241	$ 14,253	$ 11,549
Unrealized gains (losses) on securities:
Unrealized (losses) gains arising during period	198	(325)	333	(11)
Less: reclassification adjustment for gains included in net income		(27)		(27)
Total unrealized (losses) gains on securities	198	(352)	333	(38)
Accretion of net unrealized losses transferred	260	762	633	1,747
Defined benefit pension plans:
Amortization of prior service cost and loss included in net periodic benefit cost	233	243	465	485
Other comprehensive income	691	653	1,431	2,194
Comprehensive income	$ 8,848	$ 6,894	$ 15,684	$ 13,743

Amortization of prior service cost and loss included in net periodic benefit cost.

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Other comprehensive income accretion on unrealized loss for securities transferred from available for sale to held to maturity net of tax.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities and unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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