Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income, Before tax amount	$ 3,978	$ 3,494	$ 10,904	$ 10,707
Net unrealized holding (losses) gains on securities:
Unrealized holding (losses) gains arising during the period, Before tax amount	(1,770)	96	(8,033)	3,027
Reclassification adjustment for gains included in net income, Before tax amount		(98)	(3)	(962)
Other comprehensive (loss) income, Before tax amount	(1,770)	(2)	(8,036)	2,065
Unrealized holding (losses) gains arising during the period, Tax expense (benefit)	(372)	33	(1,687)	1,029
Reclassification adjustment for gains included in net income, Tax expense (benefit)		(33)	(1)	(326)
Other comprehensive (loss) income, Tax expense (benefit)	(372)		(1,688)	703
Unrealized holding (losses) gains arising during the period, Net of tax amount	(1,398)	63	(6,346)	1,998
Reclassification adjustment for gains included in net income, Net of tax amount		(65)	(2)	(636)
Other comprehensive (loss) income, Net of tax amount	(1,398)	(2)	(6,348)	1,362
Total comprehensive (loss) income, Before tax amount	2,208	3,492	2,868	12,772
Tax expense (benefit)	767	940	1,896	2,907
Total comprehensive (loss) income,Tax expense (benefit)	395	940	208	3,610
Net income	3,211	2,554	9,008	7,800
Total comprehensive (loss) income, Net of tax amount	$ 1,813	$ 2,552	$ 2,660	$ 9,162