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	$ 4,009	$ 709	$ 2,225	$ 2,327
Net change in unrealized gains on available-for-sale securities :
Unrealized gains	23	24	188	354
Income tax effect	(5)	(5)	(40)	(75)
Unrealized gains on securities, net of tax	18	19	148	279
Pension benefit liability adjustment:
Net loss		(32)		(115)
Income tax effect		7		24
Pension liability adjustment, net of tax		(25)		(91)
Total other comprehensive income, net of tax	18	(6)	148	188
Total comprehensive income	$ 4,027	$ 703	$ 2,373	$ 2,515