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Investment Securities (Details 2) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 USD ($) Investment | Dec. 31, 2016 USD ($) Investment
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 25 | 63
Available-for-sale Securities, Less than 12 months, Fair Value | $ 27,846 | $ 47,809
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 245 | $ 897
Number of investments, 12 months or longer | Investment | 28 | 2
Available-for-sale Securities, 12 months or longer, Fair Value | $ 27,511 | $ 3,991
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 518 | $ 30
Number of investments, Total | Investment | 53 | 65
Available-for-sale Securities, Fair Value, Total | $ 55,357 | $ 51,800
Available-for-sale Securities, Unrealized Losses, Total | $ 763 | $ 927
US government agencies [Member] |  |
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 5 | 5
Available-for-sale Securities, Less than 12 months, Fair Value | $ 4,184 | $ 5,144
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 22 | $ 113
Number of investments, 12 months or longer | Investment | 4 |
Available-for-sale Securities, 12 months or longer, Fair Value | $ 3,968 |
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 75 |
Number of investments, Total | Investment | 9 | 5
Available-for-sale Securities, Fair Value, Total | $ 8,152 | $ 5,144
Available-for-sale Securities, Unrealized Losses, Total | $ 97 | $ 113
SBA securities [Member] |  |
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 1 | 1
Available-for-sale Securities, Less than 12 months, Fair Value | $ 2,936 | $ 1,437
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 13 | $ 16
Number of investments, 12 months or longer | Investment | 1 |
Available-for-sale Securities, 12 months or longer, Fair Value | $ 1,127 |
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 11 |
Number of investments, Total | Investment | 2 | 1
Available-for-sale Securities, Fair Value, Total | $ 4,063 | $ 1,437
Available-for-sale Securities, Unrealized Losses, Total | $ 24 | $ 16
State and political subdivisions [Member] |  |
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 3 | 32
Available-for-sale Securities, Less than 12 months, Fair Value | $ 1,214 | $ 13,936
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 9 | $ 292
Number of investments, 12 months or longer | Investment | 2 |
Available-for-sale Securities, 12 months or longer, Fair Value | $ 792 |
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 16 |
Number of investments, Total | Investment | 5 | 32
Available-for-sale Securities, Fair Value, Total | $ 2,006 | $ 13,936
Available-for-sale Securities, Unrealized Losses, Total | $ 25 | $ 292
Mortgage-backed [Member] | FHLMC [Member] |  |
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 3 | 10
Available-for-sale Securities, Less than 12 months, Fair Value | $ 2,897 | $ 10,737
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 26 | $ 185
Number of investments, 12 months or longer | Investment | 7 |
Available-for-sale Securities, 12 months or longer, Fair Value | $ 6,056 |
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 123 |
Number of investments, Total | Investment | 10 | 10
Available-for-sale Securities, Fair Value, Total | $ 8,953 | $ 10,737
Available-for-sale Securities, Unrealized Losses, Total | $ 149 | $ 185
Mortgage-backed [Member] | FNMA [Member] |  |
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 11 | 14
Available-for-sale Securities, Less than 12 months, Fair Value | $ 14,345 | $ 15,478
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 135 | $ 247
Number of investments, 12 months or longer | Investment | 13 | 2
Available-for-sale Securities, 12 months or longer, Fair Value | $ 14,597 | $ 3,991
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 251 | $ 30
Number of investments, Total | Investment | 24 | 16
Available-for-sale Securities, Fair Value, Total | $ 29,940 | $ 19,469
Available-for-sale Securities, Unrealized Losses, Total | $ 386 | $ 277
Mortgage-backed [Member] | GNMA [Member] |  |
Summary of gross unrealized losses on investment securities and fair market value of related securities |  |
Number of investments, Less than 12 months | Investment | 2 | 1
Available-for-sale Securities, Less than 12 months, Fair Value | $ 2,270 | $ 1,077
Available-for-sale Securities, Less than 12 months, Unrealized losses | $ 40 | $ 44
Number of investments, 12 months or longer | Investment | 1 |
Available-for-sale Securities, 12 months or longer, Fair Value | $ 971 |
Available-for-sale Securities, 12 months or Longer, Unrealized losses | $ 42 |
Number of investments, Total | Investment | 3 | 1
Available-for-sale Securities, Fair Value, Total | $ 2,243 | $ 1,077
Available-for-sale Securities, Unrealized Losses, Total | $ 82 | $ 44

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