Bank segment - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Allowance for credit losses:
Beginning balance	$ 71,296	$ 67,211	$ 72,216	$ 71,130
Charge-offs	(3,203)	(1,517)	(6,625)	(3,075)
Recoveries	1,132	1,505	2,459	2,907
Provision for credit losses	(157)	2,257	1,018	(1,506)
Ending balance	69,068	69,456	69,068	69,456
Real estate | Residential 1-4 family
Allowance for credit losses:
Beginning balance	4,612	7,874	6,270	6,545
Charge-offs	(181)	0	(990)	0
Recoveries	2	3	6	11
Provision for credit losses	275	643	(578)	1,964
Ending balance	4,708	8,520	4,708	8,520
Real estate | Commercial real estate
Allowance for credit losses:
Beginning balance	22,701	20,176	21,898	24,696
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	(2,423)	724	(1,620)	(3,796)
Ending balance	20,278	20,900	20,278	20,900
Real estate | Home equity line of credit
Allowance for credit losses:
Beginning balance	6,053	5,650	6,125	5,657
Charge-offs	(297)	0	(360)	0
Recoveries	17	31	34	42
Provision for credit losses	1,366	415	1,340	397
Ending balance	7,139	6,096	7,139	6,096
Real estate | Residential land
Allowance for credit losses:
Beginning balance	620	697	717	646
Charge-offs	0	0	0	0
Recoveries	3	96	3	101
Provision for credit losses	30	(116)	(67)	(70)
Ending balance	653	677	653	677
Real estate | Commercial construction
Allowance for credit losses:
Beginning balance	735	2,340	1,195	2,186
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	1,814	294	1,354	448
Ending balance	2,549	2,634	2,549	2,634
Real estate | Residential construction
Allowance for credit losses:
Beginning balance	28	31	46	18
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	(2)	15	(20)	28
Ending balance	26	46	26	46
Commercial
Allowance for credit losses:
Beginning balance	11,936	14,314	12,426	15,798
Charge-offs	(157)	(148)	(384)	(224)
Recoveries	206	399	604	752
Provision for credit losses	(627)	(2,152)	(1,288)	(3,913)
Ending balance	11,358	12,413	11,358	12,413
Consumer
Allowance for credit losses:
Beginning balance	24,611	16,129	23,539	15,584
Charge-offs	(2,568)	(1,369)	(4,891)	(2,851)
Recoveries	904	976	1,812	2,001
Provision for credit losses	(590)	2,434	1,897	3,436
Ending balance	$ 22,357	$ 18,170	$ 22,357	$ 18,170