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Derivatives - Derivatives Associated with Fixed Income Trading Activities (Details) - USD ($) $ in Thousands | Mar. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Customer interest rate contracts |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | $ 3,395,932 | $ 2,697,522
Assets | 232,886 | 65,768
Liabilities | 1,509 | 6,858
Offsetting upstream interest rate contracts |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 3,395,932 | 2,697,522
Assets | 8,822 | 2,583
Liabilities | 16,735 | 3,994
Option contracts purchased | Long |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional |  | 40,000
Assets |  | 131
Liabilities |  | 0
Forwards and futures purchased |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 8,641,017 | 9,217,350
Assets | 156,687 | 17,029
Liabilities | 8,508 | 3,187
Forwards and futures sold |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 9,435,099 | 9,403,112
Assets | 8,829 | 3,611
Liabilities | $ 163,096 | $ 16,620

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