Bank segment - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Allowance for credit losses:
Beginning balance	$ 66,813	$ 69,068	$ 74,372	$ 72,216
Charge-offs	(3,127)	(2,792)	(9,928)	(9,417)
Recoveries	862	1,755	3,273	4,214
Provision	248	8,335	(2,921)	9,353
Ending balance	64,796	76,366	64,796	76,366
Residential 1-4 family
Allowance for credit losses:
Charge-offs			(850)
Commercial real estate
Allowance for credit losses:
Charge-offs			0
Home equity line of credit
Allowance for credit losses:
Charge-offs			0
Residential land
Allowance for credit losses:
Charge-offs			0
Commercial construction
Allowance for credit losses:
Charge-offs			0
Residential construction
Allowance for credit losses:
Charge-offs			0
Real estate | Residential 1-4 family
Allowance for credit losses:
Beginning balance	6,219	4,708	7,435	6,270
Charge-offs	(8)	0	(850)	(990)
Recoveries	9	57	202	63
Provision	(211)	1,702	(778)	1,124
Ending balance	6,009	6,467	6,009	6,467
Real estate | Commercial real estate
Allowance for credit losses:
Beginning balance	18,656	20,278	22,185	21,898
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	96	2,180	(3,433)	560
Ending balance	18,752	22,458	18,752	22,458
Real estate | Home equity line of credit
Allowance for credit losses:
Beginning balance	9,552	7,139	7,778	6,125
Charge-offs	0	0	0	(360)
Recoveries	12	131	259	165
Provision	(443)	505	1,084	1,845
Ending balance	9,121	7,775	9,121	7,775
Real estate | Residential land
Allowance for credit losses:
Beginning balance	759	653	621	717
Charge-offs	0	0	0	0
Recoveries	0	1	0	4
Provision	(147)	(33)	(9)	(100)
Ending balance	612	621	612	621
Real estate | Commercial construction
Allowance for credit losses:
Beginning balance	3,369	2,549	3,603	1,195
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(278)	1,075	(512)	2,429
Ending balance	3,091	3,624	3,091	3,624
Real estate | Residential construction
Allowance for credit losses:
Beginning balance	38	26	43	46
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(1)	16	(6)	(4)
Ending balance	37	42	37	42
Commercial
Allowance for credit losses:
Beginning balance	6,317	11,358	9,122	12,426
Charge-offs	(120)	(125)	(360)	(509)
Recoveries	100	725	385	1,329
Provision	(292)	(1,175)	(3,142)	(2,463)
Ending balance	6,005	10,783	6,005	10,783
Consumer
Allowance for credit losses:
Beginning balance	21,903	22,357	23,585	23,539
Charge-offs	(2,999)	(2,667)	(8,718)	(7,558)
Recoveries	741	841	2,427	2,653
Provision	1,524	4,065	3,875	5,962
Ending balance	$ 21,169	$ 24,596	$ 21,169	$ 24,596