Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income, Before tax amount	$ 3,982	$ 3,053
Net unrealized holding gains on securities, Before tax amount:
Unrealized holding gains arising during the period, Before tax amount	1,249	4,486
Reclassification adjustment for gains included in net income, Before tax amount	(749)	(319)
Unrealized holding gains arising during the period, Tax expense (benefit)	425	1,525
Reclassification adjustment for gains included in net income, Tax expense (benefit)	(254)	(108)
Unrealized holding gains arising during the period, Net of tax amount	824	2,961
Reclassification adjustment for gains included in net income, Net of tax amount	(495)	(211)
Other comprehensive income, Before tax amount	500	4,167
Total comprehensive income, Before tax amount	4,482	7,220
Tax expense (benefit)	1,122	788
Other comprehensive income, Tax expense (benefit)	171	1,417
Total comprehensive income, Tax expense (benefit)	1,293	2,205
Net income	2,860	2,265
Other comprehensive income, Net of tax amount	329	2,750
Total comprehensive income, Net of tax amount	$ 3,189	$ 5,015