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Derivatives - Summary of Gains and Losses on Derivative Contracts (Detail) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2018 | Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | $ 18,309 | $ 8,668
Interest Rate Swaps [Member] |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | (5) | 28
Foreign Exchange Swaps [Member] |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | 378 | 627
Foreign Exchange/Commodities Options [Member] |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | 4,599 | 3,602
Equity Options [Member] |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | 102 |
Futures [Member] |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | 5,908 | 1,949
Rate Lock Commitments and Forwards [Member] |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Gain on derivative contract | $ 7,327 | $ 2,462

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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