<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.19.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>107</ContextCount>
  <ElementCount>304</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>45</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>8</UnitCount>
  <MyReports>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - Unaudited Condensed Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/StatementUnauditedCondensedConsolidatedBalanceSheets</Role>
      <ShortName>Unaudited Condensed Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100020 - Statement - Unaudited Condensed Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/StatementUnauditedCondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Unaudited Condensed Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100030 - Statement - Unaudited Condensed Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/StatementUnauditedCondensedConsolidatedStatementsOfOperations</Role>
      <ShortName>Unaudited Condensed Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100040 - Statement - Unaudited Condensed Consolidated Statements of Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/StatementUnauditedCondensedConsolidatedStatementsOfStockholdersEquity</Role>
      <ShortName>Unaudited Condensed Consolidated Statements of Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100050 - Statement - Unaudited Condensed Consolidated Statements of Stockholders' Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/StatementUnauditedCondensedConsolidatedStatementsOfStockholdersEquityParenthetical</Role>
      <ShortName>Unaudited Condensed Consolidated Statements of Stockholders' Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>100060 - Statement - Unaudited Condensed Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/StatementUnauditedCondensedConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Unaudited Condensed Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>100070 - Disclosure - Description of Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureDescriptionOfBusiness</Role>
      <ShortName>Description of Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>100080 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>100090 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>100100 - Disclosure - Accrued Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureAccruedExpenses</Role>
      <ShortName>Accrued Expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>100110 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>100120 - Disclosure - Long-Term Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLongTermDebt</Role>
      <ShortName>Long-Term Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>100130 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>100140 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>100150 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>100160 - Disclosure - Share-based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensation</Role>
      <ShortName>Share-based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>100170 - Disclosure - Subsequent Event</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSubsequentEvent</Role>
      <ShortName>Subsequent Event</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>100180 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>100190 - Disclosure - Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesTables</Role>
      <ShortName>Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>100200 - Disclosure - Accrued Expenses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureAccruedExpensesTables</Role>
      <ShortName>Accrued Expenses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureAccruedExpenses</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>100210 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeases</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>100220 - Disclosure - Long-Term Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLongTermDebtTables</Role>
      <ShortName>Long-Term Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLongTermDebt</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>100230 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureEarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureEarningsPerShare</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>100240 - Disclosure - Share-based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensationTables</Role>
      <ShortName>Share-based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensation</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>100250 - Disclosure - Description of Business - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureDescriptionOfBusinessAdditionalInformationDetail</Role>
      <ShortName>Description of Business - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>100260 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Summary of Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>100270 - Disclosure - Summary of Disaggregates Net Sales into Major Merchandise Categories to Depict Nature and Amount of Revenue and Related Cash Flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSummaryOfDisaggregatesNetSalesIntoMajorMerchandiseCategoriesToDepictNatureAndAmountOfRevenueAndRelatedCashFlowsDetails</Role>
      <ShortName>Summary of Disaggregates Net Sales into Major Merchandise Categories to Depict Nature and Amount of Revenue and Related Cash Flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>100280 - Disclosure - Accrued Expenses - Summary of Accrued Expenses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureAccruedExpensesSummaryOfAccruedExpensesDetail</Role>
      <ShortName>Accrued Expenses - Summary of Accrued Expenses (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>100290 - Disclosure - Leases - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesAdditionalInformationDetail</Role>
      <ShortName>Leases - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>100300 - Disclosure - Leases - Summary of Components of Lease Expenses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesSummaryOfComponentsOfLeaseExpensesDetail</Role>
      <ShortName>Leases - Summary of Components of Lease Expenses (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>100310 - Disclosure - Leases - Schedule of Other Information Related to Leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesScheduleOfOtherInformationRelatedToLeasesDetail</Role>
      <ShortName>Leases - Schedule of Other Information Related to Leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>100320 - Disclosure - Leases - Schedule of Finance and Operating Lease Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesScheduleOfFinanceAndOperatingLeaseLiabilitiesDetail</Role>
      <ShortName>Leases - Schedule of Finance and Operating Lease Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>100340 - Disclosure - Leases - Schedule of Rent Expense (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesScheduleOfRentExpenseDetail</Role>
      <ShortName>Leases - Schedule of Rent Expense (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>100350 - Disclosure - Leases - Schedule of Future Minimum Lease Payments under Non-Cancelable Leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesScheduleOfFutureMinimumLeasePaymentsUnderNonCancelableLeasesDetail</Role>
      <ShortName>Leases - Schedule of Future Minimum Lease Payments under Non-Cancelable Leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>100360 - Disclosure - Leases - Schedule of Future Minimum Lease Payments under Non-Cancelable Leases (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLeasesScheduleOfFutureMinimumLeasePaymentsUnderNonCancelableLeasesParentheticalDetail</Role>
      <ShortName>Leases - Schedule of Future Minimum Lease Payments under Non-Cancelable Leases (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>100370 - Disclosure - Long-Term Debt - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLongTermDebtAdditionalInformationDetail</Role>
      <ShortName>Long-Term Debt - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>100380 - Disclosure - Long-Term Debt - Average Daily Excess Availability for Preceding Fiscal Quarter (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureLongTermDebtAverageDailyExcessAvailabilityForPrecedingFiscalQuarterDetail</Role>
      <ShortName>Long-Term Debt - Average Daily Excess Availability for Preceding Fiscal Quarter (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>100390 - Disclosure - Income Taxes - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetail</Role>
      <ShortName>Income Taxes - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>100400 - Disclosure - Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureEarningsPerShareComputationOfBasicAndDilutedEarningsPerCommonShareDetail</Role>
      <ShortName>Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>100410 - Disclosure - Share-based Compensation - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensationAdditionalInformationDetail</Role>
      <ShortName>Share-based Compensation - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>100420 - Disclosure - Share-based Compensation - Summary of Share Option Awards (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensationSummaryOfShareOptionAwardsDetail</Role>
      <ShortName>Share-based Compensation - Summary of Share Option Awards (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>100430 - Disclosure - Share-based Compensation - Fair Value of Share Option Award Based on Weighted-Average Assumptions (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensationFairValueOfShareOptionAwardBasedOnWeightedAverageAssumptionsDetail</Role>
      <ShortName>Share-based Compensation - Fair Value of Share Option Award Based on Weighted-Average Assumptions (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>100440 - Disclosure - Share-based Compensation - Summary of Nonvested Share Awards Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureShareBasedCompensationSummaryOfNonvestedShareAwardsActivityDetail</Role>
      <ShortName>Share-based Compensation - Summary of Nonvested Share Awards Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="bgfv-20190331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>100450 - Disclosure - Subsequent Event - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.big5sportinggoods.com/20190331/taxonomy/role/DisclosureSubsequentEventAdditionalInformationDetail</Role>
      <ShortName>Subsequent Event - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>bgfv-20190331.xml</File>
    <File>bgfv-20190331.xsd</File>
    <File>bgfv-20190331_cal.xml</File>
    <File>bgfv-20190331_def.xml</File>
    <File>bgfv-20190331_lab.xml</File>
    <File>bgfv-20190331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2018-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
