<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.19.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>409</ContextCount>
  <ElementCount>633</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>111</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>15</UnitCount>
  <MyReports>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001501 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - Statement - Consolidated Statements of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ConsolidatedStatementsOfComprehensiveIncomeLoss</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1002501 - Statement - Consolidated Statements of Comprehensive Income (Loss) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ConsolidatedStatementsOfComprehensiveIncomeLossParenthetical</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Loss) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1003000 - Statement - Consolidated Statements of Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ConsolidatedStatementsOfStockholdersEquity</Role>
      <ShortName>Consolidated Statements of Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1004000 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - Organization and Nature of Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OrganizationAndNatureOfBusiness</Role>
      <ShortName>Organization and Nature of Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPolicies</Role>
      <ShortName>Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2103100 - Disclosure - Recent Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RecentAccountingPronouncements</Role>
      <ShortName>Recent Accounting Pronouncements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognition</Role>
      <ShortName>Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Fair Value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/FairValue</Role>
      <ShortName>Fair Value</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/Acquisitions</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Property and Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PropertyAndEquipment</Role>
      <ShortName>Property and Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - Goodwill and Other Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssets</Role>
      <ShortName>Goodwill and Other Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - Accrued Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AccruedExpenses</Role>
      <ShortName>Accrued Expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2111100 - Disclosure - Indebtedness</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/Indebtedness</Role>
      <ShortName>Indebtedness</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - Derivative Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/DerivativeInstruments</Role>
      <ShortName>Derivative Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2114100 - Disclosure - Postretirement and Other Employee Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefits</Role>
      <ShortName>Postretirement and Other Employee Benefits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2117100 - Disclosure - Share-Based Payments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ShareBasedPayments</Role>
      <ShortName>Share-Based Payments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2118100 - Disclosure - Net Income (Loss) Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/NetIncomeLossPerShare</Role>
      <ShortName>Net Income (Loss) Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Operations by Segments and Geographic Areas</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreas</Role>
      <ShortName>Operations by Segments and Geographic Areas</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2120100 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2121100 - Disclosure - Guarantees</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/Guarantees</Role>
      <ShortName>Guarantees</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2122100 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2123100 - Disclosure - Quarterly Financial Data</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/QuarterlyFinancialData</Role>
      <ShortName>Quarterly Financial Data</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2124100 - Disclosure - Schedule II-Valuation and Qualifying Accounts Allowance for Doubtful Accounts</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ScheduleIiValuationAndQualifyingAccountsAllowanceForDoubtfulAccounts</Role>
      <ShortName>Schedule II-Valuation and Qualifying Accounts Allowance for Doubtful Accounts</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPoliciesPolicies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/SignificantAccountingPolicies</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2302302 - Disclosure - Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPoliciesTables</Role>
      <ShortName>Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/SignificantAccountingPolicies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - Recent Accounting Pronouncements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RecentAccountingPronouncementsTables</Role>
      <ShortName>Recent Accounting Pronouncements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/RecentAccountingPronouncements</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - Revenue Recognition (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionTables</Role>
      <ShortName>Revenue Recognition (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/RevenueRecognition</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - Fair Value (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/FairValueTables</Role>
      <ShortName>Fair Value (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/FairValue</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - Acquisitions Acquisitions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AcquisitionsAcquisitionsTables</Role>
      <ShortName>Acquisitions Acquisitions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Property and Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PropertyAndEquipmentTables</Role>
      <ShortName>Property and Equipment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/PropertyAndEquipment</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - Goodwill and Other Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Other Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssets</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2309301 - Disclosure - Accrued Expenses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AccruedExpensesTables</Role>
      <ShortName>Accrued Expenses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/AccruedExpenses</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2312301 - Disclosure - Derivative Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/DerivativeInstrumentsTables</Role>
      <ShortName>Derivative Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/DerivativeInstruments</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2314301 - Disclosure - Postretirement and Other Employee Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsTables</Role>
      <ShortName>Postretirement and Other Employee Benefits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefits</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2317301 - Disclosure - Share-Based Payments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ShareBasedPaymentsTables</Role>
      <ShortName>Share-Based Payments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/ShareBasedPayments</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2318301 - Disclosure - Net Income (Loss) Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/NetIncomeLossPerShareTables</Role>
      <ShortName>Net Income (Loss) Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/NetIncomeLossPerShare</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2319301 - Disclosure - Operations by Segments and Geographic Areas (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasTables</Role>
      <ShortName>Operations by Segments and Geographic Areas (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreas</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2320301 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/IncomeTaxes</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2323301 - Disclosure - Quarterly Financial Data (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/QuarterlyFinancialDataTables</Role>
      <ShortName>Quarterly Financial Data (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/QuarterlyFinancialData</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2402403 - Disclosure - Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2402404 - Disclosure - Significant Accounting Policies - Marketable Securities by Major Security Type (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPoliciesMarketableSecuritiesByMajorSecurityTypeDetail</Role>
      <ShortName>Significant Accounting Policies - Marketable Securities by Major Security Type (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2402405 - Disclosure - Significant Accounting Policies - Summary of Gross Unrealized Losses and Fair Values of Available for Sale Investments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPoliciesSummaryOfGrossUnrealizedLossesAndFairValuesOfAvailableForSaleInvestmentsDetail</Role>
      <ShortName>Significant Accounting Policies - Summary of Gross Unrealized Losses and Fair Values of Available for Sale Investments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2402406 - Disclosure - Significant Accounting Policies - Depreciation Recorded Over Estimated Useful Lives of Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SignificantAccountingPoliciesDepreciationRecordedOverEstimatedUsefulLivesOfAssetsDetail</Role>
      <ShortName>Significant Accounting Policies - Depreciation Recorded Over Estimated Useful Lives of Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - Recent Accounting Pronouncements - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RecentAccountingPronouncementsAdditionalInformationDetail</Role>
      <ShortName>Recent Accounting Pronouncements - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2403403 - Disclosure - Recent Accounting Pronouncements - Schedule of Retained Earnings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RecentAccountingPronouncementsScheduleOfRetainedEarningsDetails</Role>
      <ShortName>Recent Accounting Pronouncements - Schedule of Retained Earnings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - Revenue Recognition - Disaggregation of Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionDisaggregationOfRevenueDetails</Role>
      <ShortName>Revenue Recognition - Disaggregation of Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2404403 - Disclosure - Revenue Recognition - Remaining Performance Obligation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionRemainingPerformanceObligationDetails</Role>
      <ShortName>Revenue Recognition - Remaining Performance Obligation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2404404 - Disclosure - Revenue Recognition - Contract Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionContractAssetsAndLiabilitiesDetails</Role>
      <ShortName>Revenue Recognition - Contract Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2404405 - Disclosure - Revenue Recognition - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionAdditionalInformationDetails</Role>
      <ShortName>Revenue Recognition - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2404406 - Disclosure - Revenue Recognition - Impact of Adopting the New Revenue Standard on Condensed Consolidated Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionImpactOfAdoptingNewRevenueStandardOnCondensedConsolidatedBalanceSheetDetails</Role>
      <ShortName>Revenue Recognition - Impact of Adopting the New Revenue Standard on Condensed Consolidated Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2404407 - Disclosure - Revenue Recognition - Impact of Adopting the New Revenue Standard on Condensed Consolidated Statement of Comprehensive Income (Loss) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionImpactOfAdoptingNewRevenueStandardOnCondensedConsolidatedStatementOfComprehensiveIncomeLossDetails</Role>
      <ShortName>Revenue Recognition - Impact of Adopting the New Revenue Standard on Condensed Consolidated Statement of Comprehensive Income (Loss) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2404408 - Disclosure - Revenue Recognition - Impact of Adopting the New Revenue Standard on Condensed Consolidated Statement of Cash Flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/RevenueRecognitionImpactOfAdoptingNewRevenueStandardOnCondensedConsolidatedStatementOfCashFlowsDetails</Role>
      <ShortName>Revenue Recognition - Impact of Adopting the New Revenue Standard on Condensed Consolidated Statement of Cash Flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Fair Value Measurements (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/FairValueMeasurementsDetail</Role>
      <ShortName>Fair Value Measurements (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2405403 - Disclosure - Fair Value - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/FairValueAdditionalInformationDetail</Role>
      <ShortName>Fair Value - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - Acquisitions - Fiscal Year 2019 Acquisition - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AcquisitionsFiscalYear2019AcquisitionAdditionalInformationDetails</Role>
      <ShortName>Acquisitions - Fiscal Year 2019 Acquisition - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2406403 - Disclosure - Acquisitions Acquisitions - Pro Forma Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AcquisitionsAcquisitionsProFormaInformationDetails</Role>
      <ShortName>Acquisitions Acquisitions - Pro Forma Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2406404 - Disclosure - Acquisitions - Fiscal Year 2018 Acquisitions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AcquisitionsFiscalYear2018AcquisitionsAdditionalInformationDetails</Role>
      <ShortName>Acquisitions - Fiscal Year 2018 Acquisitions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - Property and Equipment - Schedule of Property and Equipment (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PropertyAndEquipmentScheduleOfPropertyAndEquipmentDetail</Role>
      <ShortName>Property and Equipment - Schedule of Property and Equipment (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Property and Equipment - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PropertyAndEquipmentAdditionalInformationDetail</Role>
      <ShortName>Property and Equipment - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - Goodwill and Other Intangible Assets - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - Goodwill and Other Intangible Assets - Schedule of Intangible Assets Subject to Amortization and for Intangible Assets Not Subject to Amortization (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssetsScheduleOfIntangibleAssetsSubjectToAmortizationAndForIntangibleAssetsNotSubjectToAmortizationDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Schedule of Intangible Assets Subject to Amortization and for Intangible Assets Not Subject to Amortization (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2408404 - Disclosure - Goodwill and Other Intangible Assets - Schedule of Estimated Amortization Expense (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssetsScheduleOfEstimatedAmortizationExpenseDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Schedule of Estimated Amortization Expense (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2408405 - Disclosure - Goodwill and Other Intangible Assets - Schedule of Rollforward of Goodwill Balances, by Reportable Segment (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/GoodwillAndOtherIntangibleAssetsScheduleOfRollforwardOfGoodwillBalancesByReportableSegmentDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Schedule of Rollforward of Goodwill Balances, by Reportable Segment (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - Accrued Expenses - Schedule of Accrued Expenses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/AccruedExpensesScheduleOfAccruedExpensesDetail</Role>
      <ShortName>Accrued Expenses - Schedule of Accrued Expenses (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/CommitmentsAndContingenciesAdditionalInformationDetail</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2410403 - Disclosure - Commitments and Contingencies - Schedule of Future Minimum Annual Rental Commitments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/CommitmentsAndContingenciesScheduleOfFutureMinimumAnnualRentalCommitmentsDetail</Role>
      <ShortName>Commitments and Contingencies - Schedule of Future Minimum Annual Rental Commitments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Commitments and Contingencies - Future Minimum Annual Commitments Under Long Term Service Arrangements (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/CommitmentsAndContingenciesFutureMinimumAnnualCommitmentsUnderLongTermServiceArrangementsDetail</Role>
      <ShortName>Commitments and Contingencies - Future Minimum Annual Commitments Under Long Term Service Arrangements (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>2411401 - Disclosure - Indebtedness - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IndebtednessAdditionalInformationDetail</Role>
      <ShortName>Indebtedness - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>2412402 - Disclosure - Derivative Instruments - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/DerivativeInstrumentsAdditionalInformationDetail</Role>
      <ShortName>Derivative Instruments - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>2412403 - Disclosure - Derivative Instruments - Summary of Fair Values of the Interest Rate Swap (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/DerivativeInstrumentsSummaryOfFairValuesOfInterestRateSwapDetail</Role>
      <ShortName>Derivative Instruments - Summary of Fair Values of the Interest Rate Swap (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>2412404 - Disclosure - Derivative Instruments - Summary of Effect of Derivative Interest Rate Swap in Our Consolidated Statement of Comprehensive Income (Loss) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/DerivativeInstrumentsSummaryOfEffectOfDerivativeInterestRateSwapInOurConsolidatedStatementOfComprehensiveIncomeLossDetail</Role>
      <ShortName>Derivative Instruments - Summary of Effect of Derivative Interest Rate Swap in Our Consolidated Statement of Comprehensive Income (Loss) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>2414402 - Disclosure - Postretirement and Other Employee Benefits - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsAdditionalInformationDetail</Role>
      <ShortName>Postretirement and Other Employee Benefits - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>2414403 - Disclosure - Postretirement and Other Employee Benefits - Schedule of PBO, Change in Plan Assets, Funded Status and Amounts Recognized in Consolidated Balance Sheet (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsScheduleOfPboChangeInPlanAssetsFundedStatusAndAmountsRecognizedInConsolidatedBalanceSheetDetail</Role>
      <ShortName>Postretirement and Other Employee Benefits - Schedule of PBO, Change in Plan Assets, Funded Status and Amounts Recognized in Consolidated Balance Sheet (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>2414404 - Disclosure - Postretirement and Other Employee Benefits - Summary of Weighted-Average Assumptions Used to Determine Net Benefit Costs and Benefit Obligations (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsSummaryOfWeightedAverageAssumptionsUsedToDetermineNetBenefitCostsAndBenefitObligationsDetail</Role>
      <ShortName>Postretirement and Other Employee Benefits - Summary of Weighted-Average Assumptions Used to Determine Net Benefit Costs and Benefit Obligations (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>2414405 - Disclosure - Postretirement and Other Employee Benefits - Summary of Swiss Pension Plan's Actual Asset Allocation as Compared to Profond's Target Asset Allocations (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsSummaryOfSwissPensionPlansActualAssetAllocationAsComparedToProfondsTargetAssetAllocationsDetail</Role>
      <ShortName>Postretirement and Other Employee Benefits - Summary of Swiss Pension Plan's Actual Asset Allocation as Compared to Profond's Target Asset Allocations (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>2414406 - Disclosure - Postretirement and Other Employee Benefits - Summary of Estimated Future Benefit Payments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsSummaryOfEstimatedFutureBenefitPaymentsDetail</Role>
      <ShortName>Postretirement and Other Employee Benefits - Summary of Estimated Future Benefit Payments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>2414407 - Disclosure - Postretirement and Other Employee Benefits - Components of Net Periodic Pension Costs for the Swiss Pension Plan (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/PostretirementAndOtherEmployeeBenefitsComponentsOfNetPeriodicPensionCostsForSwissPensionPlanDetail</Role>
      <ShortName>Postretirement and Other Employee Benefits - Components of Net Periodic Pension Costs for the Swiss Pension Plan (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>2417402 - Disclosure - Share Based Payments - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ShareBasedPaymentsAdditionalInformationDetail</Role>
      <ShortName>Share Based Payments - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>2417403 - Disclosure - Share Based Payments - Summary of Stock Option and Restricted Stock Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ShareBasedPaymentsSummaryOfStockOptionAndRestrictedStockActivityDetail</Role>
      <ShortName>Share Based Payments - Summary of Stock Option and Restricted Stock Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>2417404 - Disclosure - Share Based Payments - Schedule of Shares Issued as Purchase Consideration with Forfeiture Provisions (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ShareBasedPaymentsScheduleOfSharesIssuedAsPurchaseConsiderationWithForfeitureProvisionsDetail</Role>
      <ShortName>Share Based Payments - Schedule of Shares Issued as Purchase Consideration with Forfeiture Provisions (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>2418402 - Disclosure - Net Income (Loss) Per Share - Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/NetIncomeLossPerShareScheduleOfComputationOfBasicAndDilutedNetIncomeLossPerShareDetail</Role>
      <ShortName>Net Income (Loss) Per Share - Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/NetIncomeLossPerShareTables</ParentRole>
      <Position>87</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>2418403 - Disclosure - Net Income (Loss) Per Share - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/NetIncomeLossPerShareAdditionalInformationDetail</Role>
      <ShortName>Net Income (Loss) Per Share - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bottomline.com/role/NetIncomeLossPerShareTables</ParentRole>
      <Position>88</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - Operations by Segments and Geographic Areas - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasAdditionalInformationDetail</Role>
      <ShortName>Operations by Segments and Geographic Areas - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>2419403 - Disclosure - Operations by Segments and Geographic Areas - Schedule of Segment Reporting Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasScheduleOfSegmentReportingInformationDetail</Role>
      <ShortName>Operations by Segments and Geographic Areas - Schedule of Segment Reporting Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>2419404 - Disclosure - Operations by Segments and Geographic Areas - Reconciliation of Measure of Segment Profit to GAAP Income (Loss) Before Income Taxes (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasReconciliationOfMeasureOfSegmentProfitToGaapIncomeLossBeforeIncomeTaxesDetail</Role>
      <ShortName>Operations by Segments and Geographic Areas - Reconciliation of Measure of Segment Profit to GAAP Income (Loss) Before Income Taxes (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>2419405 - Disclosure - Operations by Segments and Geographic Areas - Schedule of Segment Depreciation and Amortization Expense Included in Segment Measure of Profit Loss (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasScheduleOfSegmentDepreciationAndAmortizationExpenseIncludedInSegmentMeasureOfProfitLossDetail</Role>
      <ShortName>Operations by Segments and Geographic Areas - Schedule of Segment Depreciation and Amortization Expense Included in Segment Measure of Profit Loss (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>2419406 - Disclosure - Operations by Segments and Geographic Areas - Schedule of Revenue Based on Point of Sale (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasScheduleOfRevenueBasedOnPointOfSaleDetail</Role>
      <ShortName>Operations by Segments and Geographic Areas - Schedule of Revenue Based on Point of Sale (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>2419407 - Disclosure - Operations by Segments and Geographic Areas - Schedule of Long-Lived Assets, Based on Geographical Location, Excluding Deferred Tax Assets and Intangible Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/OperationsBySegmentsAndGeographicAreasScheduleOfLongLivedAssetsBasedOnGeographicalLocationExcludingDeferredTaxAssetsAndIntangibleAssetsDetail</Role>
      <ShortName>Operations by Segments and Geographic Areas - Schedule of Long-Lived Assets, Based on Geographical Location, Excluding Deferred Tax Assets and Intangible Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>2420402 - Disclosure - Income Taxes - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesAdditionalInformationDetail</Role>
      <ShortName>Income Taxes - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>2420403 - Disclosure - Income Taxes - Schedule of Provision for (Benefit from) Income Taxes (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesScheduleOfProvisionForBenefitFromIncomeTaxesDetail</Role>
      <ShortName>Income Taxes - Schedule of Provision for (Benefit from) Income Taxes (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>2420404 - Disclosure - Income Taxes - Schedule of Income (Loss) Before Income Taxes By Geographic Area (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesScheduleOfIncomeLossBeforeIncomeTaxesByGeographicAreaDetail</Role>
      <ShortName>Income Taxes - Schedule of Income (Loss) Before Income Taxes By Geographic Area (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>2420405 - Disclosure - Income Taxes - Schedule of Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesScheduleOfReconciliationOfFederalStatutoryRateToEffectiveIncomeTaxRateDetail</Role>
      <ShortName>Income Taxes - Schedule of Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>98</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>2420406 - Disclosure - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesScheduleOfDeferredTaxAssetsAndLiabilitiesDetail</Role>
      <ShortName>Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>2420407 - Disclosure - Income Taxes - Summary of Deferred Tax Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesSummaryOfDeferredTaxAssetsDetail</Role>
      <ShortName>Income Taxes - Summary of Deferred Tax Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>100</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>2420408 - Disclosure - Income Taxes - Summary of Changes in Gross Amount of Unrecognized Tax Benefits (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/IncomeTaxesSummaryOfChangesInGrossAmountOfUnrecognizedTaxBenefitsDetail</Role>
      <ShortName>Income Taxes - Summary of Changes in Gross Amount of Unrecognized Tax Benefits (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>2422401 - Disclosure - Subsequent Events - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/SubsequentEventsAdditionalInformationDetail</Role>
      <ShortName>Subsequent Events - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>102</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>2423402 - Disclosure - Quarterly Financial Data - Schedule of Selected Quarterly Financial Data (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/QuarterlyFinancialDataScheduleOfSelectedQuarterlyFinancialDataDetail</Role>
      <ShortName>Quarterly Financial Data - Schedule of Selected Quarterly Financial Data (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>2423403 - Disclosure - Quarterly Financial Data - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/QuarterlyFinancialDataAdditionalInformationDetail</Role>
      <ShortName>Quarterly Financial Data - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>2424401 - Disclosure - Schedule II - Valuation and Qualifying Accounts Allowances for Doubtful Accounts (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bottomline.com/role/ScheduleIiValuationAndQualifyingAccountsAllowancesForDoubtfulAccountsDetail</Role>
      <ShortName>Schedule II - Valuation and Qualifying Accounts Allowances for Doubtful Accounts (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>105</Position>
    </Report>
    <Report instance="fy19q410kdoc.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9999.htm</HtmlFileName>
      <LongName>Uncategorized Items - fy19q410kdoc.htm</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/role/uncategorizedFacts</Role>
      <ShortName>Uncategorized Items - fy19q410kdoc.htm</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>106</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-K" original="fy19q410kdoc.htm">fy19q410kdoc.htm</File>
    <File>epay-20190630.xsd</File>
    <File>epay-20190630_cal.xml</File>
    <File>epay-20190630_def.xml</File>
    <File>epay-20190630_lab.xml</File>
    <File>epay-20190630_pre.xml</File>
    <File>epay-ex211.htm</File>
    <File>epay-ex231.htm</File>
    <File>epay-ex311.htm</File>
    <File>epay-ex312.htm</File>
    <File>epay-ex321.htm</File>
    <File>epay-ex322.htm</File>
    <File>epay-ex44.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>chart-36c8910010c82e53f8e.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2017-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
