Available-for-sale securities - Investment Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-Sale [Line Items]
Less than 12 Months, Fair Value	$ 19,124	$ 81,657
Less than 12 Months, Unrealized (Loss)	(1,107)	(2,318)
12 Months or Longer, Fair Value	63,632	2,702
Less than 12 Months, Unrealized (Loss)	(19,985)	(66)
Fair Value	82,756	84,359
Unrealized (Loss)	(21,092)	(2,384)
U. S. Government agency and mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Less than 12 Months, Fair Value	11,126	60,606
Less than 12 Months, Unrealized (Loss)	(633)	(1,196)
12 Months or Longer, Fair Value	47,920	1,610
Less than 12 Months, Unrealized (Loss)	(13,801)	(49)
Fair Value	59,046	62,216
Unrealized (Loss)	(14,434)	(1,245)
Corporate bonds
Debt Securities, Available-for-Sale [Line Items]
Less than 12 Months, Fair Value	1,959	15,042
Less than 12 Months, Unrealized (Loss)	(64)	(951)
12 Months or Longer, Fair Value	10,934	0
Less than 12 Months, Unrealized (Loss)	(5,061)	0
Fair Value	12,893	15,042
Unrealized (Loss)	(5,125)	(951)
Subordinated notes
Debt Securities, Available-for-Sale [Line Items]
Less than 12 Months, Fair Value	4,602	0
Less than 12 Months, Unrealized (Loss)	(398)	0
12 Months or Longer, Fair Value	0	1,092
Less than 12 Months, Unrealized (Loss)	0	(17)
Fair Value	4,602	1,092
Unrealized (Loss)	(398)	(17)
SBA loan pools
Debt Securities, Available-for-Sale [Line Items]
Less than 12 Months, Fair Value	1,437	5,603
Less than 12 Months, Unrealized (Loss)	(12)	(169)
12 Months or Longer, Fair Value	4,280	0
Less than 12 Months, Unrealized (Loss)	(1,061)	0
Fair Value	5,717	5,603
Unrealized (Loss)	(1,073)	(169)
Municipal bonds
Debt Securities, Available-for-Sale [Line Items]
Less than 12 Months, Fair Value	0	406
Less than 12 Months, Unrealized (Loss)	0	(2)
12 Months or Longer, Fair Value	498	0
Less than 12 Months, Unrealized (Loss)	(62)	0
Fair Value	498	406
Unrealized (Loss)	$ (62)	$ (2)