<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>522</ContextCount>
  <ElementCount>433</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>65</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-document-and-entity-information</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>001 - Statement - Consolidated Balance Sheets (Current Period Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-balance-sheets-current-period-unaudited</Role>
      <ShortName>Consolidated Balance Sheets (Current Period Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>002 - Statement - Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-balance-sheets-current-period-unaudited-parentheticals</Role>
      <ShortName>Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>003 - Statement - Consolidated Statements of Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-statements-of-income-unaudited</Role>
      <ShortName>Consolidated Statements of Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>004 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-statements-of-comprehensive-income-unaudited</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>005 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-statements-of-changes-in-stockholders-equity-unaudited</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>006 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-statements-of-changes-in-stockholders-equity-unaudited-parentheticals</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>007 - Statement - Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-consolidated-statements-of-cash-flows-unaudited</Role>
      <ShortName>Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>008 - Disclosure - Note 1 - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-1-basis-of-presentation</Role>
      <ShortName>Note 1 - Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>009 - Disclosure - Note 2 - Use of Estimates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-2-use-of-estimates</Role>
      <ShortName>Note 2 - Use of Estimates</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>010 - Disclosure - Note 3 - Acquisition Activity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-3-acquisition-activity</Role>
      <ShortName>Note 3 - Acquisition Activity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>011 - Disclosure - Note 4 - Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities</Role>
      <ShortName>Note 4 - Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>012 - Disclosure - Note 5 - Loans Receivable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable</Role>
      <ShortName>Note 5 - Loans Receivable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>013 - Disclosure - Note 6 - Foreclosed Real Estate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-6-foreclosed-real-estate</Role>
      <ShortName>Note 6 - Foreclosed Real Estate</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>014 - Disclosure - Note 7 - Intangibles and Acquisition Related Accounting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-7-intangibles-and-acquisition-related-accounting</Role>
      <ShortName>Note 7 - Intangibles and Acquisition Related Accounting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>015 - Disclosure - Note 8 - Concentrations of Credit Risk</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-8-concentrations-of-credit-risk</Role>
      <ShortName>Note 8 - Concentrations of Credit Risk</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>016 - Disclosure - Note 9 - Earnings per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-9-earnings-per-share</Role>
      <ShortName>Note 9 - Earnings per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>017 - Disclosure - Note 10 - Stock Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-10-stock-based-compensation</Role>
      <ShortName>Note 10 - Stock Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>018 - Disclosure - Note 11 - Change in Accounting Principles</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-11-change-in-accounting-principles</Role>
      <ShortName>Note 11 - Change in Accounting Principles</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>019 - Disclosure - Note 12 - Upcoming Accounting Standards</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-12-upcoming-accounting-standards</Role>
      <ShortName>Note 12 - Upcoming Accounting Standards</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>020 - Disclosure - Note 13 - Derivative Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-13-derivative-financial-instruments-</Role>
      <ShortName>Note 13 - Derivative Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>021 - Disclosure - Note 14 - Fair Value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value</Role>
      <ShortName>Note 14 - Fair Value</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>022 - Disclosure - Note 3 - Acquisition Activity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-3-acquisition-activity-tables</Role>
      <ShortName>Note 3 - Acquisition Activity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-3-acquisition-activity</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>023 - Disclosure - Note 4 - Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-tables</Role>
      <ShortName>Note 4 - Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>024 - Disclosure - Note 5 - Loans Receivable (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-tables</Role>
      <ShortName>Note 5 - Loans Receivable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>025 - Disclosure - Note 6 - Foreclosed Real Estate (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-6-foreclosed-real-estate-tables</Role>
      <ShortName>Note 6 - Foreclosed Real Estate (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-6-foreclosed-real-estate</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>026 - Disclosure - Note 7 - Intangibles and Acquisition Related Accounting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-7-intangibles-and-acquisition-related-accounting-tables</Role>
      <ShortName>Note 7 - Intangibles and Acquisition Related Accounting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-7-intangibles-and-acquisition-related-accounting</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>027 - Disclosure - Note 9 - Earnings per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-9-earnings-per-share-tables</Role>
      <ShortName>Note 9 - Earnings per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-9-earnings-per-share</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>028 - Disclosure - Note 10 - Stock Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-10-stock-based-compensation-tables</Role>
      <ShortName>Note 10 - Stock Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-10-stock-based-compensation</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>029 - Disclosure - Note 13 - Derivative Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-13-derivative-financial-instruments-tables</Role>
      <ShortName>Note 13 - Derivative Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-13-derivative-financial-instruments-</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>030 - Disclosure - Note 14 - Fair Value (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-tables</Role>
      <ShortName>Note 14 - Fair Value (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>031 - Disclosure - Note 3 - Acquisition Activity (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-3-acquisition-activity-details-textual</Role>
      <ShortName>Note 3 - Acquisition Activity (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-3-acquisition-activity-tables</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>032 - Disclosure - Note 3 - Acquisition Activity - Fair Value of Tangible and Intangible Assets Acquired and Liabilities Assumed From AJSB (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-3-acquisition-activity-fair-value-of-tangible-and-intangible-assets-acquired-and-liabilities-assumed-from-ajsb-details</Role>
      <ShortName>Note 3 - Acquisition Activity - Fair Value of Tangible and Intangible Assets Acquired and Liabilities Assumed From AJSB (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>033 - Disclosure - Note 4 - Securities (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-details-textual</Role>
      <ShortName>Note 4 - Securities (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-tables</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>034 - Disclosure - Note 4 - Securities - Available for Sale Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-available-for-sale-securities-details</Role>
      <ShortName>Note 4 - Securities - Available for Sale Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>035 - Disclosure - Note 4 - Securities - Estimated Fair Value of Available for Sale Securities, by Contractual Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-estimated-fair-value-of-available-for-sale-securities-by-contractual-maturity-details</Role>
      <ShortName>Note 4 - Securities - Estimated Fair Value of Available for Sale Securities, by Contractual Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>036 - Disclosure - Note 4 - Securities - Sales of Available for Sale Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-sales-of-available-for-sale-securities-details</Role>
      <ShortName>Note 4 - Securities - Sales of Available for Sale Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>037 - Disclosure - Note 4 - Securities - Available for Sale Securities, Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-available-for-sale-securities-accumulated-other-comprehensive-income-loss-balances-net-of-tax-details</Role>
      <ShortName>Note 4 - Securities - Available for Sale Securities, Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>038 - Disclosure - Note 4 - Securities - Securities with Gross Unrealized Losses Not Recognized in Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-4-securities-securities-with-gross-unrealized-losses-not-recognized-in-income-details</Role>
      <ShortName>Note 4 - Securities - Securities with Gross Unrealized Losses Not Recognized in Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>039 - Disclosure - Note 5 - Loans Receivable (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-details-textual</Role>
      <ShortName>Note 5 - Loans Receivable (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-tables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>040 - Disclosure - Note 5 - Loans Receivable - Loans Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-loans-receivable-details</Role>
      <ShortName>Note 5 - Loans Receivable - Loans Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>041 - Disclosure - Note 5 - Loans Receivable - Allowance for Loan Losses, by Loan Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-allowance-for-loan-losses-by-loan-segment-details</Role>
      <ShortName>Note 5 - Loans Receivable - Allowance for Loan Losses, by Loan Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>042 - Disclosure - Note 5 - Loans Receivable - Impairment Analysis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-impairment-analysis-details</Role>
      <ShortName>Note 5 - Loans Receivable - Impairment Analysis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>043 - Disclosure - Note 5 - Loans Receivable - Credit Quality Indicators (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-credit-quality-indicators-details</Role>
      <ShortName>Note 5 - Loans Receivable - Credit Quality Indicators (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>044 - Disclosure - Note 5 - Loans Receivable - Individually Evaluated Impaired Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-individually-evaluated-impaired-loans-details</Role>
      <ShortName>Note 5 - Loans Receivable - Individually Evaluated Impaired Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>045 - Disclosure - Note 5 - Loans Receivable - Age Analysis of Past Due Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-age-analysis-of-past-due-loans-details</Role>
      <ShortName>Note 5 - Loans Receivable - Age Analysis of Past Due Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>046 - Disclosure - Note 5 - Loans Receivable - Loans on Nonaccrual Status (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-loans-on-nonaccrual-status-details</Role>
      <ShortName>Note 5 - Loans Receivable - Loans on Nonaccrual Status (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>047 - Disclosure - Note 5 - Loans Receivable - Accretable Yield (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-accretable-yield-details</Role>
      <ShortName>Note 5 - Loans Receivable - Accretable Yield (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>048 - Disclosure - Note 5 - Loans Receivable - Net Fair Value Discount on Loans Receivable Acquired (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-5-loans-receivable-net-fair-value-discount-on-loans-receivable-acquired-details</Role>
      <ShortName>Note 5 - Loans Receivable - Net Fair Value Discount on Loans Receivable Acquired (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>049 - Disclosure - Note 6 - Foreclosed Real Estate - Foreclosed Real Estate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-6-foreclosed-real-estate-foreclosed-real-estate-details</Role>
      <ShortName>Note 6 - Foreclosed Real Estate - Foreclosed Real Estate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>050 - Disclosure - Note 7 - Intangibles and Acquisition Related Accounting (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-7-intangibles-and-acquisition-related-accounting-details-textual</Role>
      <ShortName>Note 7 - Intangibles and Acquisition Related Accounting (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-7-intangibles-and-acquisition-related-accounting-tables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>051 - Disclosure - Note 7 - Intangibles and Acquisition Related Accounting - Annual Amortization (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-7-intangibles-and-acquisition-related-accounting-annual-amortization-details</Role>
      <ShortName>Note 7 - Intangibles and Acquisition Related Accounting - Annual Amortization (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>052 - Disclosure - Note 9 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings per Common Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-9-earnings-per-share-reconciliation-of-basic-and-diluted-earnings-per-common-share-details</Role>
      <ShortName>Note 9 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings per Common Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>053 - Disclosure - Note 10 - Stock Based Compensation (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-10-stock-based-compensation-details-textual</Role>
      <ShortName>Note 10 - Stock Based Compensation (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-10-stock-based-compensation-tables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>054 - Disclosure - Note 10 - Stock Based Compensation - Restricted Stock Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-10-stock-based-compensation-restricted-stock-activity-details</Role>
      <ShortName>Note 10 - Stock Based Compensation - Restricted Stock Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>055 - Disclosure - Note 13 - Derivative Financial Instruments - Non-hedging Derivative Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-13-derivative-financial-instruments-nonhedging-derivative-financial-instruments-details</Role>
      <ShortName>Note 13 - Derivative Financial Instruments - Non-hedging Derivative Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>056 - Disclosure - Note 13 - Derivative Financial Instruments - Offset Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-13-derivative-financial-instruments-offset-assets-details</Role>
      <ShortName>Note 13 - Derivative Financial Instruments - Offset Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>057 - Disclosure - Note 13 - Derivative Financial Instruments - Offset Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-13-derivative-financial-instruments-offset-liabilities-details</Role>
      <ShortName>Note 13 - Derivative Financial Instruments - Offset Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>058 - Disclosure - Note 14 - Fair Value (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-details-textual</Role>
      <ShortName>Note 14 - Fair Value (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-tables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>059 - Disclosure - Note 14 - Fair Value - Credit Loss Roll Forward for Trust Preferred Securities Classified with Other Than Temporary Impairment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-credit-loss-roll-forward-for-trust-preferred-securities-classified-with-other-than-temporary-impairment-details</Role>
      <ShortName>Note 14 - Fair Value - Credit Loss Roll Forward for Trust Preferred Securities Classified with Other Than Temporary Impairment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>060 - Disclosure - Note 14 - Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-assets-measured-at-fair-value-on-a-recurring-basis-details</Role>
      <ShortName>Note 14 - Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>061 - Disclosure - Note 14 - Fair Value - Available for Sale Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-available-for-sale-securities-details</Role>
      <ShortName>Note 14 - Fair Value - Available for Sale Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>062 - Disclosure - Note 14 - Fair Value - Assets Measured on a Nonrecurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-assets-measured-on-a-nonrecurring-basis-details</Role>
      <ShortName>Note 14 - Fair Value - Assets Measured on a Nonrecurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="nwin-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>063 - Disclosure - Note 14 - Fair Value - Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ibankpeoples.com/20200331/role/statement-note-14-fair-value-financial-instruments-details</Role>
      <ShortName>Note 14 - Fair Value - Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>nwin-20200331.xml</File>
    <File>nwin-20200331.xsd</File>
    <File>nwin-20200331_cal.xml</File>
    <File>nwin-20200331_def.xml</File>
    <File>nwin-20200331_lab.xml</File>
    <File>nwin-20200331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
