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Investment Securities - Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale (Detail) - USD ($) $ in Thousands | 6 Months Ended
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Jun. 30, 2016 | Jun. 30, 2015
Investments, Debt and Equity Securities [Abstract] |  |
Proceeds from Sale of Available-for-sale Securities | $ 55,744 | $ 0
Sales Transactions: |  |
Gross gains | 304 | 0
Gross losses | (276) | 0
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments | 28 | 0
Maturities and impairment |  |
Gross Gains | 0 | 105
Gross Losses | 0 | 0
Other Than Temporary Impairment | 0 | 0
Gain Losses Maturities And Impairment | 0 | 105
Net gains and impairment | $ 28 | $ 105

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- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
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