Derivative Instruments - Cash flow hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Effects of derivative instruments
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ 684	$ (223)	$ (3,088)	$ (1,907)
Interest rate contracts
Effects of derivative instruments
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ 684	$ (223)	$ (3,088)	$ (1,907)