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Investment Securities - Summary of Interest Income on Available-For-Sale Investment Securities (Details) - USD ($) $ in Thousands | 9 Months Ended
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Sep. 30, 2017 | Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items] |  |
Total taxable interest income | $ 3,136 | $ 2,650
Total tax-exempt interest income | 281 | 213
Total interest income | 3,417 | 2,863
U.S. Treasury and government sponsored entities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total taxable interest income | 2,255 | 1,979
U.S. Agency mortgage-backed securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total taxable interest income | 0 | 4
Other |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total taxable interest income | 881 | 667
Municipal securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total tax-exempt interest income | $ 281 | $ 213

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