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Summary of Significant Accounting Policies - Accounting Pronouncements (Details) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Jan. 01, 2018
Net interest income | $ 27,261,000 | $ 21,800,000 | $ 50,403,000 | $ 42,416,000 |
Net income | $ 6,261,000 | $ 5,146,000 | $ 15,750,000 | $ 9,573,000 |
Diluted earnings per share (in dollars per share) | $ 0.21 | $ 0.17 | $ 0.52 | $ 0.32 |
Accounting Standards Update 2017-08 | Previously reported |  |  |  |  |
Net interest income |  | $ 22,100,000 |  | $ 42,900,000 |
Net income |  | $ 5,500,000 |  | $ 10,000,000 |
Diluted earnings per share (in dollars per share) |  | $ 0.18 |  | $ 0.33 |
Accounting Standards Update 2018-02 | Accumulated Other Comprehensive Income (Loss) |  |  |  |  |
Cumulative effect of new accounting principle |  |  |  |  | $ 319,000
Accounting Standards Update 2018-02 | Retained Earnings |  |  |  |  |
Cumulative effect of new accounting principle |  |  |  |  | $ (319,000)

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