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Derivatives (Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | $ 2,995 | $ 3,316 | $ 7,879 | $ 8,107
Interest rate contracts | Interest rate contracts and other derivative income |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | (1,359) | 88 | (3,138) | 1,194
Foreign exchange contracts | Foreign exchange income |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | 3,495 | 2,646 | 9,821 | 6,503
Credit contracts | Interest rate contracts and other derivative income |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | (36) | (56) | 47 | (69)
Equity contracts | Lending fees |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | 917 | 598 | 1,167 | 439
Commodity contracts | Interest rate contracts and other derivative income |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | $ (22) | $ 40 | $ (18) | $ 40

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- Definition Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4CC -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998890-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959 + Details
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