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Note 21 - Business Combination - Pro Forma Information (Details) - Community Shores Bank Corp ("Community Shores") [Member] - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Net interest income | $ 54,357 | $ 51,266
Noninterest income | 23,462 | 14,722
Noninterest expense | 55,182 | 49,865
Net income | $ 15,257 | $ 14,250
Net income per diluted share (in dollars per share) | $ 1.96 | $ 1.83

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