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Effect of Derivative Instruments on Consolidated Statements of Operations and Comprehensive Income (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
(Loss) Gain Included in Mortgage Banking Income | $ (5,954) | $ (12,154) | $ (1,969)
Treasury Options |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
(Loss) Gain Included in Mortgage Banking Income | (262) | (2,795) | (8,222)
Eurodollar Futures |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
(Loss) Gain Included in Mortgage Banking Income | 55 | 165 | 501
Interest Rate Swap |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
(Loss) Gain Included in Mortgage Banking Income | 3,068 | (4,561) |
Forward commitments to buy/sell loans/mortgage-backed securities |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
(Loss) Gain Included in Mortgage Banking Income | $ (8,815) | $ (4,963) | $ 5,752

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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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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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