Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,077	$ 1,004
Other comprehensive income (loss):
Unrealized income (losses) arising during the period on available-for-sale securities, net of income taxes impact, respectively	1,819	(1,788)
Reclassification adjustment for net gain on sales of available-for-sale securities included in net income, net of income taxes impact, respectively	(6)	(78)
Change in defined benefit plans, net of income taxes impact, respectively	(6)	(1)
Total other comprehensive income (loss)	1,807	(1,867)
Total comprehensive income (loss)	$ 5,884	$ (863)