Other Derivatives - Designated cash flow hedges (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Designated Cash Flow Hedge
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income	$ (60)	$ (394)	$ (445)	$ (366)
Interest Expenses
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Total amounts of income and expense line items presented in the consolidated statement of income in which the effects of fair value or cash flow hedges are recorded	(60)	(394)	(445)	(366)
Interest Expenses | Designated Cash Flow Hedge
Reclassification of Cash Flow Hedge Gain (Loss) [Abstract]
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income	(60)	(394)	(445)	(366)
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income as a result that a forecasted transaction is no longer probable of occurring	0	0	0	0
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income - Included Component	(60)	(394)	(445)	(366)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income - Excluded Component	$ 0	$ 0	$ 0	$ 0