Bank segment - Collateral-dependent loans (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Residential real estate property | Real estate | Residential 1-4 family
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	$ 4,699	$ 3,493
Residential real estate property | Real estate | Home equity line of credit
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	899	1,294
Residential real estate property | Real estate | Residential land
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	97	300
Commercial real estate | Real estate | Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	0	1,221
Collateral pledged
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	5,882	7,000
Collateral pledged | Real estate
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	5,695	6,308
Business assets | Commercial
Financing Receivable, Nonaccrual [Line Items]
Collateral-dependent loans, amortized cost	$ 187	$ 692