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Derivative Instruments and Hedging Activities - Amount of Gain or Loss Recognized in Income on Derivatives (Detail) - Not Designated as Hedging Instruments [Member] - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Total Derivatives Gain (Loss) | $ 63 | $ 124 | $ 194 | $ 95
Interest Rate Swap Contracts-Commercial Loans [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Total Derivatives Gain (Loss) | (21) | (11) | (8) | (19)
Interest Rate Lock Commitments [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Total Derivatives Gain (Loss) | (8) | 199 | 128 | 207
Forward Sale Contracts-Mortgage Loans [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Total Derivatives Gain (Loss) | $ 92 | $ (64) | $ 74 | $ (93)

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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=56946850&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=56946850&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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