Derivatives and hedging activities - Fair Values of Derivative Instruments (Details) $ in Thousands	Mar. 31, 2026 USD ($) security	Dec. 31, 2025 USD ($)
Derivatives, Fair Value
Asset derivatives fair value	$ 14,702	$ 15,896
Liability derivatives fair value	14,584	15,988
Interest rate swaps
Derivatives, Fair Value
Asset derivatives fair value	14,373	15,583
Derivatives designated as hedging instruments \| Other Liabilities.
Derivatives, Fair Value
Liability derivatives fair value	158	329
Derivatives designated as hedging instruments \| Interest rate products \| Other Liabilities.
Derivatives, Fair Value
Notional amount	25,000
Liability derivatives fair value	158	329
Derivatives not designated as hedging instruments \| Other Assets.
Derivatives, Fair Value
Asset derivatives fair value	14,704	15,898
Derivatives not designated as hedging instruments \| Other Liabilities.
Derivatives, Fair Value
Liability derivatives fair value	14,425	15,659
Derivatives not designated as hedging instruments \| Interest rate products \| Other Assets.
Derivatives, Fair Value
Notional amount	408,661	368,500
Asset derivatives fair value	14,702	15,896
Derivatives not designated as hedging instruments \| Interest rate products \| Other Liabilities.
Derivatives, Fair Value
Notional amount	408,661
Liability derivatives fair value	14,425	15,659
Derivatives not designated as hedging instruments \| Other contracts \| Other Assets.
Derivatives, Fair Value
Notional amount	37,321	34,000
Asset derivatives fair value	2	$ 2
Derivatives not designated as hedging instruments \| Other contracts \| Other Liabilities.
Derivatives, Fair Value
Notional amount	$ 6,919
Derivatives not designated as hedging instruments \| Interest rate swaps
Derivatives, Fair Value
Number of instruments held \| security	179
Asset derivatives fair value	$ 446,000
Liability derivatives fair value	$ 415,600

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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