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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
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Mar. 31, 2018 | Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items] |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | $ 4,791 | $ 4,773
Interest rate swaps and options | Derivative fees and other income |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | 1,106 | (1,066)
Foreign exchange spot and forwards | Letters of credit fees and foreign exchange income |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | 3,857 | 5,838
Credit risk participation agreements | Derivative fees and other income |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | (13) | 1
Equity warrants | Ancillary loan fees and other income |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | (159) | 0
Commodity options | Derivative fees and other income |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Net gains (losses) recognized for derivative not designated as hedging instruments | $ 0 | $ 0

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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/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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