Bank segment - Allowance for Loan Commitments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for loan commitments:
Beginning balance	$ 4,600	$ 5,900	$ 4,400	$ 4,900
Provision	500	(1,500)	700	(500)
Ending balance	5,100	4,400	5,100	4,400
Real estate \| Home equity line of credit
Allowance for loan commitments:
Beginning balance	600	400	400	400
Provision	0	0	200	0
Ending balance	600	400	600	400
Real estate \| Commercial construction
Allowance for loan commitments:
Beginning balance	3,800	4,100	2,600	3,700
Provision	500	(1,500)	1,700	(1,100)
Ending balance	4,300	2,600	4,300	2,600
Commercial
Allowance for loan commitments:
Beginning balance	200	1,400	1,400	800
Provision	0	0	(1,200)	600
Ending balance	$ 200	$ 1,400	$ 200	$ 1,400

Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482454/460-10-45-1

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Amount of expense (reversal of expense) for expected credit loss for off-balance sheet credit exposure. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

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