Bank segment - Credit risk profile - payment activity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Credit risk profile based on payment activity for loans
Total financing receivables	$ 6,087,727	$ 6,005,021
Amortized cost> 90 days and accruing	0	0
Real estate
Credit risk profile based on payment activity for loans
Total financing receivables	5,014,377	4,970,621
Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	2,484,316	2,479,637
Amortized cost> 90 days and accruing	0	0
Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	1,377,184	1,358,123
Amortized cost> 90 days and accruing	0	0
Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	1,022,800	1,002,905
Amortized cost> 90 days and accruing	0	0
Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	20,061	20,679
Amortized cost> 90 days and accruing	0	0
Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	94,267	88,489
Amortized cost> 90 days and accruing	0	0
Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	15,749	20,788
Amortized cost> 90 days and accruing	0	0
Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	800,949	779,691
Amortized cost> 90 days and accruing	0	0
Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	272,401	254,709
Amortized cost> 90 days and accruing	0	0
30-59 days past due
Credit risk profile based on payment activity for loans
Total financing receivables	5,567	5,959
30-59 days past due | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	1,909	1,546
30-59 days past due | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	0	508
30-59 days past due | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	896	1,312
30-59 days past due | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
30-59 days past due | Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
30-59 days past due | Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
30-59 days past due | Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	263	614
30-59 days past due | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	2,499	1,979
60-89 days past due
Credit risk profile based on payment activity for loans
Total financing receivables	3,024	2,343
60-89 days past due | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	930	358
60-89 days past due | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	0	217
60-89 days past due | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	683	435
60-89 days past due | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
60-89 days past due | Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
60-89 days past due | Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
60-89 days past due | Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	71	18
60-89 days past due | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	1,340	1,315
Greater than 90 days
Credit risk profile based on payment activity for loans
Total financing receivables	4,572	5,624
Greater than 90 days | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	1,955	3,205
Greater than 90 days | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Greater than 90 days | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	970	1,213
Greater than 90 days | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Greater than 90 days | Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Greater than 90 days | Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Greater than 90 days | Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	427	77
Greater than 90 days | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	1,220	1,129
Total past due
Credit risk profile based on payment activity for loans
Total financing receivables	13,163	13,926
Total past due | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	4,794	5,109
Total past due | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	0	725
Total past due | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	2,549	2,960
Total past due | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Total past due | Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Total past due | Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
Total past due | Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	761	709
Total past due | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	5,059	4,423
Current
Credit risk profile based on payment activity for loans
Total financing receivables	6,074,564	5,991,095
Current | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	2,479,522	2,474,528
Current | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	1,377,184	1,357,398
Current | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	1,020,251	999,945
Current | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	20,061	20,679
Current | Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	94,267	88,489
Current | Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	15,749	20,788
Current | Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	800,188	778,982
Current | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	$ 267,342	$ 250,286