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Securities - Summary of Amortized Costs and Fair Values of Securities (Detail) - USD ($) $ in Thousands | Sep. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Securities available for sale: |  |  |
Amortized Cost | $ 93,485 | $ 96,106 |
Gross Unrealized Gains | 452 | 333 |
Gross Unrealized (Losses) | (835) | (1,637) |
Fair Value | 93,102 | 94,802 | [1]
Securities held to maturity: |  |  |
Amortized Cost | 49,376 | 53,398 |
Gross Unrealized Gains | 287 | 19 |
Gross Unrealized (Losses) | (247) | (708) |
Fair Value | 49,416 | 52,709 | [1]
Total securities, Amortized cost | 142,861 | 149,504 |
Total securities, Gross unrealized gains | 739 | 352 |
Total securities, Gross unrealized (losses) | (1,082) | (2,345) |
Total securities, Fair value | 142,518 | 147,511 |
U.S. agency and mortgage-backed securities |  |  |
Securities available for sale: |  |  |
Amortized Cost | 78,039 | 81,451 |
Gross Unrealized Gains | 235 | 177 |
Gross Unrealized (Losses) | (767) | (1,457) |
Fair Value | 77,507 | 80,171 |
Securities held to maturity: |  |  |
Amortized Cost | 33,300 | 37,269 |
Gross Unrealized Gains | 48 | 1 |
Gross Unrealized (Losses) | (234) | (483) |
Fair Value | 33,114 | 36,787 |
Obligations of states and political subdivisions |  |  |
Securities available for sale: |  |  |
Amortized Cost | 15,445 | 14,654 |
Gross Unrealized Gains | 203 | 146 |
Gross Unrealized (Losses) | (68) | (180) |
Fair Value | 15,580 | 14,620 |
Securities held to maturity: |  |  |
Amortized Cost | 14,576 | 14,629 |
Gross Unrealized Gains | 239 | 18 |
Gross Unrealized (Losses) | (1) | (211) |
Fair Value | 14,814 | 14,436 |
Corporate equity securities |  |  |
Securities available for sale: |  |  |
Amortized Cost | 1 | 1 |
Gross Unrealized Gains | 14 | 10 |
Gross Unrealized (Losses) | 0 | 0 |
Fair Value | 15 | 11 |
Corporate debt securities |  |  |
Securities held to maturity: |  |  |
Amortized Cost | 1,500 | 1,500 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized (Losses) | (12) | (14) |
Fair Value | $ 1,488 | $ 1,486 |
[1] | Derived from audited consolidated financial statements.

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