Bank segment - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for credit losses:
Beginning balance	$ 69,068	$ 69,456	$ 72,216	$ 71,130
Charge-offs	(2,792)	(1,646)	(9,417)	(4,721)
Recoveries	1,755	1,282	4,214	4,189
Provision	8,335	1,314	9,353	(192)
Ending balance	76,366	70,406	76,366	70,406
Real estate \| Residential 1-4 family
Allowance for credit losses:
Beginning balance	4,708	8,520	6,270	6,545
Charge-offs	0	0	(990)	0
Recoveries	57	2	63	13
Provision	1,702	(938)	1,124	1,026
Ending balance	6,467	7,584	6,467	7,584
Real estate \| Commercial real estate
Allowance for credit losses:
Beginning balance	20,278	20,900	21,898	24,696
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	2,180	136	560	(3,660)
Ending balance	22,458	21,036	22,458	21,036
Real estate \| Home equity line of credit
Allowance for credit losses:
Beginning balance	7,139	6,096	6,125	5,657
Charge-offs	0	0	(360)	0
Recoveries	131	14	165	56
Provision	505	(167)	1,845	230
Ending balance	7,775	5,943	7,775	5,943
Real estate \| Residential land
Allowance for credit losses:
Beginning balance	653	677	717	646
Charge-offs	0	0	0	0
Recoveries	1	0	4	101
Provision	(33)	12	(100)	(58)
Ending balance	621	689	621	689
Real estate \| Commercial construction
Allowance for credit losses:
Beginning balance	2,549	2,634	1,195	2,186
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	1,075	(1,635)	2,429	(1,187)
Ending balance	3,624	999	3,624	999
Real estate \| Residential construction
Allowance for credit losses:
Beginning balance	26	46	46	18
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	16	3	(4)	31
Ending balance	42	49	42	49
Commercial
Allowance for credit losses:
Beginning balance	11,358	12,413	12,426	15,798
Charge-offs	(125)	(143)	(509)	(367)
Recoveries	725	303	1,329	1,055
Provision	(1,175)	378	(2,463)	(3,535)
Ending balance	10,783	12,951	10,783	12,951
Consumer
Allowance for credit losses:
Beginning balance	22,357	18,170	23,539	15,584
Charge-offs	(2,667)	(1,503)	(7,558)	(4,354)
Recoveries	841	963	2,653	2,964
Provision	4,065	3,525	5,962	6,961
Ending balance	$ 24,596	$ 21,155	$ 24,596	$ 21,155

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

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+ References

No definition available.

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- Definition

Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

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

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- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

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- Definition

Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ 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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