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Securities - Unrealized Gains (Losses) of Debt Securities (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
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Investments, Debt and Equity Securities [Abstract] |  |
Total unrealized gains (losses) on debt securities available-for-sale, Gross Unrealized Gains | $ 2,858 | $ 5,645
Total unrealized gains (losses) on debt securities available-for-sale, Gross Unrealized Losses | (12,950) | (3,967)
Total unrealized gains (losses) on debt securities available-for-sale, Net Unrealized Gains/(Losses) | (10,092) | 1,678
Income tax (expense) benefit, Gross Unrealized Gains | (607) | (1,982)
Income tax (expense) benefit, Gross Unrealized Losses | 2,750 | 1,393
Income tax (expense) benefit, Net Unrealized Gains/(Losses) | 2,143 | (589)
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss), Gross Unrealized Gains | 2,251 | 3,663
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss), Gross Unrealized Losses | (10,200) | (2,574)
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss), Net Unrealized Gains/(Losses) | $ (7,949) | $ 1,089

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