Derivatives and hedging activities - Credit-risk-related Contingent Features (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Derivatives
Derivative Liability	$ 20,633,000	$ 21,466,000
Cash collateral	17,590,000	14,530,000
Credit-risk contract
Derivatives
Derivative Liability	2,700,000	2,000.0
Cash collateral	$ 2,500,000	$ 0