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Derivatives - Gains/(Losses) on Derivatives Associated with Interest Rate Risk Management Activities (Details) - Hedging Instruments And Hedged Items - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019
Customer Interest Rate Contracts Hedging | Customer interest rate contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) related to interest rate derivatives | $ 15,844 | $ 50,706 | $ 211,396 | $ 79,818
Customer Interest Rate Contracts Hedging | Offsetting upstream interest rate contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) related to interest rate derivatives | (15,844) | (50,706) | (211,396) | (79,818)
Debt Hedging | Interest Rate Swap |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) related to interest rate derivatives | (737) | 6,697 | 4,197 | 10,976
Debt Hedging | Term Borrowings |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains/(Losses) related to term borrowings | $ 720 | $ (6,605) | $ (3,745) | $ (10,871)

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