Derivatives and hedging activities - Effect of Fair Value and Cash Flow Hedge Accounting on the Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss)
Total amounts of income and expense line items presented in the statements of income and comprehensive income in which the effects of fair value or cash flow hedges are recorded	$ (493)	$ 242
Interest income
Derivative Instruments, Gain (Loss)
Total amounts of income and expense line items presented in the statements of income and comprehensive income in which the effects of fair value or cash flow hedges are recorded	131	134
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income	131	134
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income - included component	147	150
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income - excluded component	$ (16)	(16)
Interest expense
Derivative Instruments, Gain (Loss)
Total amounts of income and expense line items presented in the statements of income and comprehensive income in which the effects of fair value or cash flow hedges are recorded		(23)
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income		$ (23)