Securities - Additional Information (Detail) - USD ($) |
3 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2014 |
Mar. 31, 2016 |
Mar. 31, 2015 |
Dec. 31, 2015 |
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| Investment Securities [Line Items] | ||||
| Impairment charges on securities in continuous unrealized loss position for 12 months or longer | $ 0 | $ 0 | ||
| Net realized gains on sales of securities | 0 | $ 2,184,000 | ||
| Recognized in earnings resulting from the sale of securities | $ 535,000 | $ 535,000 | ||
| Securities available for sale | 675,032,000 | 698,296,000 | ||
| Securities Pledged as Collateral [Member] | ||||
| Investment Securities [Line Items] | ||||
| Securities available for sale | $ 70,200,000 | $ 72,000,000 | ||
| X | ||||||||||
- Definition Amount of accumulated pre-tax unrealized loss on investments in available-for-sale securities that have been in a loss position for twelve months or longer. No definition available.
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| X | ||||||||||
- Definition Investment Securities [Line Items] No definition available.
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| X | ||||||||||
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities and unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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