Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 6,504	$ 8,661	$ 14,337	$ 18,330
Other comprehensive income, net of reclassification adjustment:
Unrealized holding gains on available for sale securities	4,695	6,299	8,438	12,441
Tax effect	(986)	(1,323)	(1,772)	(2,612)
Pension liability adjustment	72	147	145	294
Tax effect	(15)	(31)	(31)	(62)
Total other comprehensive income	3,766	5,092	6,780	10,061
Comprehensive income	$ 10,270	$ 13,753	$ 21,117	$ 28,391