Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income, Before tax amount	$ 4,196	$ 3,492
Net unrealized holding gains (losses) on securities:
Unrealized holding gains (losses) arising during the period, Before tax amount	4,391	(5,048)
Reclassification adjustment for losses included in net income, Before tax amount	39	1
Other comprehensive income (loss), Before tax amount	4,430	(5,047)
Unrealized holding gains (losses) arising during the period, Tax expense (benefit)	922	(1,060)
Reclassification adjustment for losses included in net income, Tax expense (benefit)	8
Other comprehensive income (loss), Tax expense (benefit)	930	(1,060)
Unrealized holding gains (losses) arising during the period, Net of tax amount	3,469	(3,988)
Reclassification adjustment for losses included in net income, Net of tax amount	31	1
Other comprehensive income (loss), Net of tax amount	3,500	(3,987)
Total comprehensive income (loss), Before tax amount	8,626	(1,555)
Tax expense (benefit)	817	557
Total comprehensive income (loss), Tax expense (benefit)	1,747	(503)
Net income	3,379	2,935
Total comprehensive income (loss), Net of tax amount	$ 6,879	$ (1,052)