Bank segment - Credit risk profile - payment activity (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Credit risk profile based on payment activity for loans
Total financing receivables	$ 5,199,026	$ 5,345,226
Amortized cost> 90 days and accruing	0	0
Real estate
Credit risk profile based on payment activity for loans
Total financing receivables	4,209,835	4,239,745
Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	2,122,873	2,144,239
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	1,071,716	983,865
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	870,182	963,578
Amortized cost> 90 days and accruing	0	0
Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	18,865	15,617
Amortized cost> 90 days and accruing	0	0
Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	115,625	121,424
Amortized cost> 90 days and accruing	0	0
Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	10,574	11,022
Amortized cost> 90 days and accruing	0	0
Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	856,336	936,748
Amortized cost> 90 days and accruing	0	0
Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	132,855	168,733
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	5,905	7,394
30-59 days past due | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	3,198	2,629
30-59 days past due | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	0	0
30-59 days past due | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	881	850
30-59 days past due | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	0	702
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	298	608
30-59 days past due | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	1,528	2,605
60-89 days past due
Credit risk profile based on payment activity for loans
Total financing receivables	3,860	5,411
60-89 days past due | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	1,813	2,790
60-89 days past due | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	0	488
60-89 days past due | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	104	342
60-89 days past due | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	696	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	224	300
60-89 days past due | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	1,023	1,491
Greater than 90 days
Credit risk profile based on payment activity for loans
Total financing receivables	12,284	6,830
Greater than 90 days | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	9,259	2,715
Greater than 90 days | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	170	0
Greater than 90 days | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	1,509	2,052
Greater than 90 days | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	300	300
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	116	132
Greater than 90 days | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	930	1,631
Current
Credit risk profile based on payment activity for loans
Total financing receivables	5,176,977	5,325,591
Current | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	2,108,603	2,136,105
Current | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	1,071,546	983,377
Current | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	867,688	960,334
Current | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	17,869	14,615
Current | Real estate | Commercial construction
Credit risk profile based on payment activity for loans
Total financing receivables	115,625	121,424
Current | Real estate | Residential construction
Credit risk profile based on payment activity for loans
Total financing receivables	10,574	11,022
Current | Commercial
Credit risk profile based on payment activity for loans
Total financing receivables	855,698	935,708
Current | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	129,374	163,006
Total past due
Credit risk profile based on payment activity for loans
Total financing receivables	22,049	19,635
Total past due | Real estate | Residential 1-4 family
Credit risk profile based on payment activity for loans
Total financing receivables	14,270	8,134
Total past due | Real estate | Commercial real estate
Credit risk profile based on payment activity for loans
Total financing receivables	170	488
Total past due | Real estate | Home equity line of credit
Credit risk profile based on payment activity for loans
Total financing receivables	2,494	3,244
Total past due | Real estate | Residential land
Credit risk profile based on payment activity for loans
Total financing receivables	996	1,002
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	638	1,040
Total past due | Consumer
Credit risk profile based on payment activity for loans
Total financing receivables	$ 3,481	$ 5,727