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Investment Securities - Additional Information (Detail) (USD $) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2014 | Sep. 30, 2013 | Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract] |  |  |
Decrease In Yield On Investment Due To Sales | 0.07% |  |
Proceeds from sales | $ 132,868,000 | $ 671,000 |
Available-for-sale securities pledged as collateral | $ 547,100,000 |  | $ 594,900,000
Decrease In Life Of Portfolio Due To Sales | 2 months 12 days |  |

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- Definition The fair value of available-for-sale securities that serve as collateral for borrowings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5086-111524 + Details
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- Definition The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26853-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585 + Details
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