Accumulated Other Comprehensive Loss - Comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Changes in the components of accumulated other comprehensive loss, net of tax
Balance	$ 43,479	$ 29,886
Net current-period other comprehensive income (loss)	(1,774)	10
Balance	42,115	41,947
Securities Available-for-Sale
Changes in the components of accumulated other comprehensive loss, net of tax
Balance	215	723
Other comprehensive income (loss) before reclassifications	(1,774)	(13)
Net current-period other comprehensive income (loss)	(1,774)	(13)
Balance	(1,559)	710
Defined Benefit Pension Plan
Changes in the components of accumulated other comprehensive loss, net of tax
Balance	(1,181)	(2,138)
Amounts reclassified from AOCI to the income statement		23
Net current-period other comprehensive income (loss)		23
Balance	(1,181)	(2,115)
Accumulated Other Comprehensive Income (Loss)
Changes in the components of accumulated other comprehensive loss, net of tax
Balance	(966)	(1,415)
Other comprehensive income (loss) before reclassifications	(1,774)	(13)
Amounts reclassified from AOCI to the income statement		23
Net current-period other comprehensive income (loss)	(1,774)	10
Balance	$ (2,740)	$ (1,405)