SBA loan servicing activities - Schedule of net gain on sale of SBA loans (Details) - SBA Loan - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Servicing Asset at Amortized Cost [Line Items]
Gain on sale of guaranteed SBA loans	$ 3,435	$ 2,087
Loss on sale of unguaranteed SBA loans	(406)	(70)
Costs recognized on sale of SBA loans	(51)	(895)
Fair value of servicing rights created	1,229	530
Net gain realized on sale of residential loans held for sale	$ 4,207	$ 1,652

The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(h))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.3(a))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

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