Bank segment - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Allowance for credit losses:
Beginning balance	$ 71,057	$ 71,296	$ 74,372	$ 72,216
Charge-offs	(3,126)	(3,203)	(6,801)	(6,625)
Recoveries	892	1,132	2,411	2,459
Provision	(2,010)	(157)	(3,169)	1,018
Ending balance	66,813	69,068	66,813	69,068
Residential 1-4 family
Allowance for credit losses:
Charge-offs			(842)
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	6,406	4,612	7,435	6,270
Charge-offs	0	(181)	(842)	(990)
Recoveries	7	2	193	6
Provision	(194)	275	(567)	(578)
Ending balance	6,219	4,708	6,219	4,708
Real estate | Commercial real estate
Allowance for credit losses:
Beginning balance	20,334	22,701	22,185	21,898
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(1,678)	(2,423)	(3,529)	(1,620)
Ending balance	18,656	20,278	18,656	20,278
Real estate | Home equity line of credit
Allowance for credit losses:
Beginning balance	8,073	6,053	7,778	6,125
Charge-offs	0	(297)	0	(360)
Recoveries	9	17	247	34
Provision	1,470	1,366	1,527	1,340
Ending balance	9,552	7,139	9,552	7,139
Real estate | Residential land
Allowance for credit losses:
Beginning balance	672	620	621	717
Charge-offs	0	0	0	0
Recoveries	0	3	0	3
Provision	87	30	138	(67)
Ending balance	759	653	759	653
Real estate | Commercial construction
Allowance for credit losses:
Beginning balance	3,401	735	3,603	1,195
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(32)	1,814	(234)	1,354
Ending balance	3,369	2,549	3,369	2,549
Real estate | Residential construction
Allowance for credit losses:
Beginning balance	41	28	43	46
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(3)	(2)	(5)	(20)
Ending balance	38	26	38	26
Commercial
Allowance for credit losses:
Beginning balance	7,614	11,936	9,122	12,426
Charge-offs	(126)	(157)	(240)	(384)
Recoveries	190	206	285	604
Provision	(1,361)	(627)	(2,850)	(1,288)
Ending balance	6,317	11,358	6,317	11,358
Consumer
Allowance for credit losses:
Beginning balance	24,516	24,611	23,585	23,539
Charge-offs	(3,000)	(2,568)	(5,719)	(4,891)
Recoveries	686	904	1,686	1,812
Provision	(299)	(590)	2,351	1,897
Ending balance	$ 21,903	$ 22,357	$ 21,903	$ 22,357