Bank segment - Credit Risk Profile - Payment Activity and Assigned Grades (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Credit risk profile by internally assigned grade for loans
Current year	$ 75,345	$ 638,750
One year before current year	630,920	1,212,344
Two years before current year	1,176,407	1,081,072
Three years before current year	1,066,554	747,623
Four years before current year	738,844	234,179
Prior	1,254,463	1,081,789
Revolving	1,130,260	1,145,385
Converted to term loans	72,462	69,436
Total	6,145,255	6,210,578
30-59 days past due
Credit risk profile by internally assigned grade for loans
Total	6,761	8,712
60-89 days past due
Credit risk profile by internally assigned grade for loans
Total	3,666	8,148
Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Total	24,812	23,073
Real estate | Residential 1-4 family
Credit risk profile by internally assigned grade for loans
Current year	43,536	263,605
One year before current year	260,253	411,257
Two years before current year	403,815	732,821
Three years before current year	724,507	401,163
Four years before current year	396,319	104,976
Prior	769,661	681,340
Revolving	0	0
Converted to term loans	0	0
Total	2,598,091	2,595,162
Real estate | Residential 1-4 family | Current
Credit risk profile by internally assigned grade for loans
Current year	43,536	263,605
One year before current year	260,253	407,304
Two years before current year	401,887	729,256
Three years before current year	722,614	399,766
Four years before current year	395,190	104,487
Prior	761,888	672,408
Revolving	0	0
Converted to term loans	0	0
Total	2,585,368	2,576,826
Real estate | Residential 1-4 family | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	708
Two years before current year	0	0
Three years before current year	0	268
Four years before current year	0	0
Prior	2,191	3,525
Revolving	0	0
Converted to term loans	0	0
Total	2,191	4,501
Real estate | Residential 1-4 family | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	726
Two years before current year	0	2,694
Three years before current year	0	0
Four years before current year	0	0
Prior	773	1,745
Revolving	0	0
Converted to term loans	0	0
Total	773	5,165
Real estate | Residential 1-4 family | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	2,519
Two years before current year	1,928	871
Three years before current year	1,893	1,129
Four years before current year	1,129	489
Prior	4,809	3,662
Revolving	0	0
Converted to term loans	0	0
Total	9,759	8,670
Real estate | Home equity line of credit
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	932,778	957,388
Converted to term loans	63,271	59,819
Total	996,049	1,017,207
Real estate | Home equity line of credit | Current
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	929,649	954,461
Converted to term loans	62,087	59,146
Total	991,736	1,013,607
Real estate | Home equity line of credit | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	971	1,219
Converted to term loans	700	262
Total	1,671	1,481
Real estate | Home equity line of credit | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	740	597
Converted to term loans	169	0
Total	909	597
Real estate | Home equity line of credit | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	1,418	1,111
Converted to term loans	315	411
Total	1,733	1,522
Real estate | Residential land
Credit risk profile by internally assigned grade for loans
Current year	1,955	3,788
One year before current year	3,748	4,772
Two years before current year	4,563	7,234
Three years before current year	5,467	1,847
Four years before current year	1,746	0
Prior	718	723
Revolving	0	0
Converted to term loans	0	0
Total	18,197	18,364
Real estate | Residential land | Current
Credit risk profile by internally assigned grade for loans
Current year	1,955	3,788
One year before current year	3,748	4,097
Two years before current year	3,888	7,234
Three years before current year	5,467	1,847
Four years before current year	1,746	0
Prior	718	723
Revolving	0	0
Converted to term loans	0	0
Total	17,522	17,689
Real estate | Residential land | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Residential land | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	675
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	675
Real estate | Residential land | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	675	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	675	0
Real estate | Residential construction
Credit risk profile by internally assigned grade for loans
Current year	388	5,369
One year before current year	6,189	10,984
Two years before current year	10,440	1,490
Three years before current year	739	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	17,756	17,843
Real estate | Residential construction | Current
Credit risk profile by internally assigned grade for loans
Current year	388	5,369
One year before current year	6,189	10,984
Two years before current year	10,440	1,490
Three years before current year	739	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	17,756	17,843
Real estate | Residential construction | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Residential construction | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Residential construction | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Commercial real estate
Credit risk profile by internally assigned grade for loans
Current year	8,436	104,368
One year before current year	104,489	386,119
Two years before current year	384,828	193,683
Three years before current year	192,636	267,458
Four years before current year	265,611	90,783
Prior	396,912	316,145
Revolving	15,482	15,482
Converted to term loans	0	0
Total	1,368,394	1,374,038
Real estate | Commercial real estate | Pass
Credit risk profile by internally assigned grade for loans
Current year	8,436	104,368
One year before current year	104,489	384,144
Two years before current year	382,853	180,986
Three years before current year	191,109	267,458
Four years before current year	265,611	65,625
Prior	363,035	307,367
Revolving	15,482	15,482
Converted to term loans	0	0
Total	1,331,015	1,325,430
Real estate | Commercial real estate | Special Mention
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	1,975
Two years before current year	1,975	11,159
Three years before current year	0	0
Four years before current year	0	14,110
Prior	17,338	3,008
Revolving	0	0
Converted to term loans	0	0
Total	19,313	30,252
Real estate | Commercial real estate | Substandard
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	1,538
Three years before current year	1,527	0
Four years before current year	0	11,048
Prior	13,991	5,770
Revolving	0	0
Converted to term loans	0	0
Total	15,518	18,356
Real estate | Commercial real estate | Doubtful
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	2,548	0
Revolving	0	0
Converted to term loans	0	0
Total	2,548	0
Real estate | Commercial real estate | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Total	0	0
Real estate | Commercial real estate | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Total	0	0
Real estate | Commercial real estate | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Total	11,048	11,048
Real estate | Commercial construction
Credit risk profile by internally assigned grade for loans
Current year	0	45,863
One year before current year	55,494	33,240
Two years before current year	39,399	26,133
Three years before current year	26,545	1,333
Four years before current year	1,333	0
Prior	0	0
Revolving	63,086	65,836
Converted to term loans	0	0
Total	185,857	172,405
Real estate | Commercial construction | Pass
Credit risk profile by internally assigned grade for loans
Current year	0	45,863
One year before current year	55,494	33,240
Two years before current year	39,399	26,133
Three years before current year	26,545	1,333
Four years before current year	1,333	0
Prior	0	0
Revolving	63,086	65,836
Converted to term loans	0	0
Total	185,857	172,405
Real estate | Commercial construction | Special Mention
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Commercial construction | Substandard
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Commercial construction | Doubtful
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	0	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	0	0
Real estate | Commercial construction | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Total	0	0
Real estate | Commercial construction | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Total	0	0
Real estate | Commercial construction | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Total	0	0
Consumer
Credit risk profile by internally assigned grade for loans
Current year	9,034	89,230
One year before current year	78,524	156,225
Two years before current year	145,293	10,243
Three years before current year	8,526	1,748
Four years before current year	1,179	530
Prior	430	200
Revolving	10,519	10,846
Converted to term loans	2,768	3,234
Total	256,273	272,256
Consumer | Current
Credit risk profile by internally assigned grade for loans
Current year	8,829	87,686
One year before current year	76,930	153,239
Two years before current year	141,903	9,852
Three years before current year	8,207	1,654
Four years before current year	1,127	451
Prior	406	200
Revolving	10,207	10,663
Converted to term loans	2,395	2,779
Total	250,004	266,524
Consumer | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Current year	205	805
One year before current year	612	1,314
Two years before current year	1,559	176
Three years before current year	167	29
Four years before current year	11	24
Prior	11	0
Revolving	152	56
Converted to term loans	110	163
Total	2,827	2,567
Consumer | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	385
One year before current year	613	886
Two years before current year	1,150	114
Three years before current year	84	41
Four years before current year	15	21
Prior	3	0
Revolving	70	60
Converted to term loans	49	69
Total	1,984	1,576
Consumer | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Current year	0	354
One year before current year	369	786
Two years before current year	681	101
Three years before current year	68	24
Four years before current year	26	34
Prior	10	0
Revolving	90	67
Converted to term loans	214	223
Total	1,458	1,589
Commercial
Credit risk profile by internally assigned grade for loans
Current year	11,996	126,527
One year before current year	122,223	209,747
Two years before current year	188,069	109,468
Three years before current year	108,134	74,074
Four years before current year	72,656	37,890
Prior	86,742	83,381
Revolving	108,395	95,833
Converted to term loans	6,423	6,383
Total	704,638	743,303
Commercial | Pass
Credit risk profile by internally assigned grade for loans
Current year	11,996	124,667
One year before current year	102,699	199,796
Two years before current year	178,426	106,669
Three years before current year	105,411	73,976
Four years before current year	72,558	37,580
Prior	83,332	80,012
Revolving	99,943	87,206
Converted to term loans	6,284	6,250
Total	660,649	716,156
Commercial | Special Mention
Credit risk profile by internally assigned grade for loans
Current year	0	1,860
One year before current year	19,524	6,989
Two years before current year	6,774	951
Three years before current year	933	0
Four years before current year	0	250
Prior	228	0
Revolving	7,176	7,352
Converted to term loans	0	0
Total	34,635	17,402
Commercial | Substandard
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	2,962
Two years before current year	2,869	1,848
Three years before current year	1,790	98
Four years before current year	0	60
Prior	3,182	3,369
Revolving	1,276	1,275
Converted to term loans	139	133
Total	9,256	9,745
Commercial | Doubtful
Credit risk profile by internally assigned grade for loans
Current year	0	0
One year before current year	0	0
Two years before current year	0	0
Three years before current year	0	0
Four years before current year	98	0
Prior	0	0
Revolving	0	0
Converted to term loans	0	0
Total	98	0
Commercial | 30-59 days past due
Credit risk profile by internally assigned grade for loans
Total	72	163
Commercial | 60-89 days past due
Credit risk profile by internally assigned grade for loans
Total	0	135
Commercial | Greater than 89 days past due
Credit risk profile by internally assigned grade for loans
Total	$ 139	$ 244