Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 7,682	$ 7,708	$ 22,019	$ 26,038
Other comprehensive income, net of reclassification adjustment:
Unrealized holding gains on available for sale securities	856	3,724	9,294	16,164
Tax effect	(180)	(782)	(1,952)	(3,393)
Pension liability adjustment	72	147	217	441
Tax effect	(15)	(31)	(46)	(93)
Total other comprehensive income	733	3,058	7,513	13,119
Comprehensive income	$ 8,415	$ 10,766	$ 29,532	$ 39,157