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Derivative Instruments - Cash flow hedges (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Effects of derivative instruments |  |  |  |
Amount of (Loss) Gain Recognized in OCI on Derivatives (Effective Portion) | $ (678) | $ (309) | $ (2,396) | $ 874
Cash Flow Hedging |  |  |  |
Effects of derivative instruments |  |  |  |
Amount of (Loss) Gain Recognized in OCI on Derivatives (Effective Portion) | (223) | 221 | (1,907) | 1,636
Amount of Gain Recognized from Accumulated OCI into Income (Effective Portion) | 119 | 113 | 516 | 182
Cash Flow Hedging | Interest rate contracts |  |  |  |
Effects of derivative instruments |  |  |  |
Amount of (Loss) Gain Recognized in OCI on Derivatives (Effective Portion) | (223) | 221 | (1,907) | 1,636
Cash Flow Hedging | Interest rate contracts | Interest expense |  |  |  |
Effects of derivative instruments |  |  |  |
Amount of Gain Recognized from Accumulated OCI into Income (Effective Portion) | $ 119 | $ 113 | $ 516 | $ 182

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