Derivative Instruments - Cash flow hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Effects of derivative instruments
Amount of Loss Recognized in OCI on Derivatives (Effective Portion)	$ 454	$ 1,071	$ 3,772	$ 1,684
Interest rate contracts
Effects of derivative instruments
Amount of Loss Recognized in OCI on Derivatives (Effective Portion)	$ 454	$ 1,071	$ 3,772	$ 1,684