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Business and Summary of Significant Accounting Policies - Nature of business (Details) |  | 12 Months Ended
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Jun. 14, 2017 USD ($) $ / shares | Dec. 31, 2017 item
Nature of business |  |
Merger transaction, the number of shares into which each share of common stock issued and outstanding prior to merger was converted | 0.20 |
Merger transaction, cash paid to stockholders for remaining fractional shares | $ | $ 2,000 |
Offering price per share | $ / shares | $ 19.00 |
Chicago metropolitan area |  |
Nature of business |  |
Number of bank branches |  | 55
Wisconsin |  |
Nature of business |  |
Number of bank branches |  | 1

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- Definition Merger Transaction, cash paid to stockholders for remaining fractional shares. + References No definition available. + Details
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- Definition Ratio applied to the conversion of common stock in merger transaction. It is the number of shares into which one share of common stock issued and outstanding prior to the effective time of merger was converted. + References No definition available. + Details
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- References No definition available. + Details
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- Definition Represents the number of bank branches. + References No definition available. + Details
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- Definition Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
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- Details
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- Details
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