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Note 2 - Business Combination (Details) - Pro Forma Information (Firstbank Corporation [Member], USD $) | 3 Months Ended | 9 Months Ended
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Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013
Firstbank Corporation [Member] |  |  |  |
Note 2 - Business Combination (Details) - Pro Forma Information [Line Items] |  |  |  |
Net interest income | $ 25,989,000 | $ 11,994,000 | $ 54,924,000 | $ 37,080,000
Noninterest expense | 24,572,000 | 14,284,000 | 47,338,000 | 32,944,000
Net income | $ 3,281,000 | $ 693,000 | $ 11,711,000 | $ 9,617,000
Net income per diluted share (in Dollars per share) | $ 0.19 | $ 0.04 | $ 0.69 | $ 0.57

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