Bank segment - Allowance for Loan Commitments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Allowance for loan commitments:
Beginning balance	$ 4,200	$ 4,600	$ 5,100	$ 4,400
Provision	0	500	(900)	700
Ending balance	4,200	5,100	4,200	5,100
Real estate \| Home equity line of credit
Allowance for loan commitments:
Beginning balance	700	600	600	400
Provision	0	0	100	200
Ending balance	700	600	700	600
Real estate \| Commercial construction
Allowance for loan commitments:
Beginning balance	3,100	3,800	4,300	2,600
Provision	0	500	(1,200)	1,700
Ending balance	3,100	4,300	3,100	4,300
Commercial
Allowance for loan commitments:
Beginning balance	400	200	200	1,400
Provision	0	0	200	(1,200)
Ending balance	$ 400	$ 200	$ 400	$ 200

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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