<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Version>2.4.0.8</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>557</ContextCount>
  <ElementCount>389</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>89</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>101 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DocumentandEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>103 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/StatementOfFinancialPositionUnclassified-DepositBasedOperations</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>104 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/StatementOfFinancialPositionUnclassified-DepositBasedOperationsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>105 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/StatementOfIncomeInterestBasedRevenue</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>106 - Statement - Consolidated Statements of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/StatementOfOtherComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Loss)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>107 - Statement - Consolidated Statement of Changes in Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncome</Role>
      <ShortName>Consolidated Statement of Changes in Stockholders' Equity</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>108 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/StatementOfCashFlowsIndirectDepositBasedOperations</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>109 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsBasisOfPresentationAndSignificantAccountingPoliciesTextBlock</Role>
      <ShortName>Basis of Presentation and Summary of Significant Accounting Policies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>110 - Disclosure - Going Concern Considerations and Future Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsOtherItemsDisclosureTextBlock</Role>
      <ShortName>Going Concern Considerations and Future Plans</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>111 - Disclosure - Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsInvestmentTextBlock</Role>
      <ShortName>Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>112 - Disclosure - Loans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsLoansNotesTradeAndOtherReceivablesDisclosureTextBlock</Role>
      <ShortName>Loans</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>113 - Disclosure - Other Real Estate Owned</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsRealEstateOwnedTextBlock</Role>
      <ShortName>Other Real Estate Owned</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>114 - Disclosure - Deposits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsDepositLiabilitiesDisclosuresTextBlock</Role>
      <ShortName>Deposits</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>115 - Disclosure - Advances from the Federal Home Loan Bank</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsFederalHomeLoanBankAdvancesDisclosureTextBlock</Role>
      <ShortName>Advances from the Federal Home Loan Bank</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>116 - Disclosure - Fair Values Measurement</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlock</Role>
      <ShortName>Fair Values Measurement</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>117 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlock</Role>
      <ShortName>Income Taxes</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>118 - Disclosure - Stock Plans and Stock Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock</Role>
      <ShortName>Stock Plans and Stock Based Compensation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>119 - Disclosure - Earnings (Loss) per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlock</Role>
      <ShortName>Earnings (Loss) per Share</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>120 - Disclosure - Capital Requirements and Restrictions on Retained Earnings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock</Role>
      <ShortName>Capital Requirements and Restrictions on Retained Earnings</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>121 - Disclosure - Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsLossContingencyDisclosures</Role>
      <ShortName>Contingencies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>122 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsBasisOfPresentationAndSignificantAccountingPoliciesTextBlockPolicies</Role>
      <ShortName>Basis of Presentation and Summary of Significant Accounting Policies (Policies)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>123 - Disclosure - Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsInvestmentTextBlockTables</Role>
      <ShortName>Securities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>124 - Disclosure - Loans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsLoansNotesTradeAndOtherReceivablesDisclosureTextBlockTables</Role>
      <ShortName>Loans (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>125 - Disclosure - Other Real Estate Owned (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsRealEstateOwnedTextBlockTables</Role>
      <ShortName>Other Real Estate Owned (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>126 - Disclosure - Deposits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsDepositLiabilitiesDisclosuresTextBlockTables</Role>
      <ShortName>Deposits (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>127 - Disclosure - Advances from the Federal Home Loan Bank (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsFederalHomeLoanBankAdvancesDisclosureTextBlockTables</Role>
      <ShortName>Advances from the Federal Home Loan Bank (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>128 - Disclosure - Fair Values Measurement (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlockTables</Role>
      <ShortName>Fair Values Measurement (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>129 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlockTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>130 - Disclosure - Stock Plans and Stock Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlockTables</Role>
      <ShortName>Stock Plans and Stock Based Compensation (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>131 - Disclosure - Earnings (Loss) per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlockTables</Role>
      <ShortName>Earnings (Loss) per Share (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>132 - Disclosure - Capital Requirements and Restrictions on Retained Earnings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/NotesToFinancialStatementsRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlockTables</Role>
      <ShortName>Capital Requirements and Restrictions on Retained Earnings (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>133 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesAdditionalInformation</Role>
      <ShortName>Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>134 - Disclosure - Going Concern Considerations and Future Plans - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureGoingConcernConsiderationsAndFuturePlansAdditionalInformation</Role>
      <ShortName>Going Concern Considerations and Future Plans - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>135 - Disclosure - Fair Value of Available for Sale Securities, Held to Maturity Securities and Related Gross Unrealized Gains and Losses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureFairValueOfAvailableForSaleSecuritiesHeldToMaturitySecuritiesAndRelatedGrossUnrealizedGainsAndLosses</Role>
      <ShortName>Fair Value of Available for Sale Securities, Held to Maturity Securities and Related Gross Unrealized Gains and Losses (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>136 - Disclosure - Sales and Calls of Available for Sale Securities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureSalesAndCallsOfAvailableForSaleSecurities</Role>
      <ShortName>Sales and Calls of Available for Sale Securities (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>137 - Disclosure - Amortized Cost and Fair Value of Debt Investment Securities Portfolio by Contractual Maturity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureAmortizedCostAndFairValueOfDebtInvestmentSecuritiesPortfolioByContractualMaturity</Role>
      <ShortName>Amortized Cost and Fair Value of Debt Investment Securities Portfolio by Contractual Maturity (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>138 - Disclosure - Securities - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureSecuritiesAdditionalInformation</Role>
      <ShortName>Securities - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>139 - Disclosure - Securities with Unrealized Losses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureSecuritiesWithUnrealizedLosses</Role>
      <ShortName>Securities with Unrealized Losses (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>140 - Disclosure - Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureLoans</Role>
      <ShortName>Loans (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>141 - Disclosure - Activity in Allowance for Loan Losses by Portfolio Segment (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureActivityInAllowanceForLoanLossesByPortfolioSegment</Role>
      <ShortName>Activity in Allowance for Loan Losses by Portfolio Segment (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>142 - Disclosure - Balance in Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureBalanceInAllowanceForLoanLossesAndRecordedInvestmentInLoansByPortfolioSegmentAndBasedOnImpairmentMethod</Role>
      <ShortName>Balance in Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>143 - Disclosure - Loans Individually Evaluated for Impairment by Class of Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureLoansIndividuallyEvaluatedForImpairmentByClassOfLoans</Role>
      <ShortName>Loans Individually Evaluated for Impairment by Class of Loans (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>144 - Disclosure - Types of Troubled Debt Restructuring Loan Modification by Portfolio Segment Outstanding (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureTypesOfTroubledDebtRestructuringLoanModificationByPortfolioSegmentOutstanding</Role>
      <ShortName>Types of Troubled Debt Restructuring Loan Modification by Portfolio Segment Outstanding (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>145 - Disclosure - Loans - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureLoansAdditionalInformation</Role>
      <ShortName>Loans - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>146 - Disclosure - Recorded Investment in Nonaccrual and Loans Past due 90 Days and Still on Accrual by Class of Loan (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureRecordedInvestmentInNonaccrualAndLoansPastDue90DaysAndStillOnAccrualByClassOfLoan</Role>
      <ShortName>Recorded Investment in Nonaccrual and Loans Past due 90 Days and Still on Accrual by Class of Loan (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>147 - Disclosure - Aging of Recorded Investment in Past Due Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureAgingOfRecordedInvestmentInPastDueLoans</Role>
      <ShortName>Aging of Recorded Investment in Past Due Loans (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>148 - Disclosure - Risk Category of Loans by Class of Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureRiskCategoryOfLoansByClassOfLoans</Role>
      <ShortName>Risk Category of Loans by Class of Loans (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>149 - Disclosure - Major Categories of Other Real Estate Owned (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureMajorCategoriesOfOtherRealEstateOwned</Role>
      <ShortName>Major Categories of Other Real Estate Owned (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>150 - Disclosure - Other Real Estate Owned Valuation Allowance Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureOtherRealEstateOwnedValuationAllowanceActivity</Role>
      <ShortName>Other Real Estate Owned Valuation Allowance Activity (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>151 - Disclosure - Net Activity Relating to Other Real Estate Owned Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureNetActivityRelatingToOtherRealEstateOwnedActivity</Role>
      <ShortName>Net Activity Relating to Other Real Estate Owned Activity (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>152 - Disclosure - Expenses Related to Other Real Estate Owned (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureExpensesRelatedToOtherRealEstateOwned</Role>
      <ShortName>Expenses Related to Other Real Estate Owned (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>153 - Disclosure - Scheduled of Deposits by Category (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureScheduledOfDepositsByCategory</Role>
      <ShortName>Scheduled of Deposits by Category (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>154 - Disclosure - Deposits - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureDepositsAdditionalInformation</Role>
      <ShortName>Deposits - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>155 - Disclosure - Scheduled Maturities of Total Time Deposits (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureScheduledMaturitiesOfTotalTimeDeposits</Role>
      <ShortName>Scheduled Maturities of Total Time Deposits (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>156 - Disclosure - Advances from Federal Home Loan Bank (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureAdvancesFromFederalHomeLoanBank</Role>
      <ShortName>Advances from Federal Home Loan Bank (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>157 - Disclosure - Advances from Federal Home Loan Bank (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureAdvancesFromFederalHomeLoanBankParenthetical</Role>
      <ShortName>Advances from Federal Home Loan Bank (Parenthetical) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>158 - Disclosure - Advances from the Federal Home Loan Bank - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureAdvancesFromTheFederalHomeLoanBankAdditionalInformation</Role>
      <ShortName>Advances from the Federal Home Loan Bank - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>159 - Disclosure - Fair Values Measurement - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureFairValuesMeasurementAdditionalInformation</Role>
      <ShortName>Fair Values Measurement - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>160 - Disclosure - Financial Assets Measured at Fair Value on Recurring and Non Recurring Basis (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureFinancialAssetsMeasuredAtFairValueOnRecurringAndNonRecurringBasis</Role>
      <ShortName>Financial Assets Measured at Fair Value on Recurring and Non Recurring Basis (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>161 - Disclosure - Reconciliation of all Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs Level 3 (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureReconciliationOfAllAssetsMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsLevel3</Role>
      <ShortName>Reconciliation of all Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs Level 3 (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>162 - Disclosure - Qualitative Information About Level Three Fair Value Measurements for Financial Instruments Measured at Fair Value on Non-Recurring Basis (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureQualitativeInformationAboutLevelThreeFairValueMeasurementsForFinancialInstrumentsMeasuredAtFairValueOnNonRecurringBasis</Role>
      <ShortName>Qualitative Information About Level Three Fair Value Measurements for Financial Instruments Measured at Fair Value on Non-Recurring Basis (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>163 - Disclosure - Carrying Amount and Estimated Fair Values of Financial Instruments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureCarryingAmountAndEstimatedFairValuesOfFinancialInstruments</Role>
      <ShortName>Carrying Amount and Estimated Fair Values of Financial Instruments (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>164 - Disclosure - Deferred Tax Assets and Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureDeferredTaxAssetsAndLiabilities</Role>
      <ShortName>Deferred Tax Assets and Liabilities (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>165 - Disclosure - Income Taxes - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureIncomeTaxesAdditionalInformation</Role>
      <ShortName>Income Taxes - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>166 - Disclosure - Stock Plans and Stock Based Compensation - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureStockPlansAndStockBasedCompensationAdditionalInformation</Role>
      <ShortName>Stock Plans and Stock Based Compensation - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>167 - Disclosure - Summary of Unvested Share Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureSummaryOfUnvestedShareActivity</Role>
      <ShortName>Summary of Unvested Share Activity (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>168 - Disclosure - Summary of Unvested Share Activity for Non-Employee Directors (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureSummaryOfUnvestedShareActivityForNonEmployeeDirectors</Role>
      <ShortName>Summary of Unvested Share Activity for Non-Employee Directors (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>169 - Disclosure - Unrecognized Stock Based Compensation Expense Related to Unvested Shares (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureUnrecognizedStockBasedCompensationExpenseRelatedToUnvestedShares</Role>
      <ShortName>Unrecognized Stock Based Compensation Expense Related to Unvested Shares (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>170 - Disclosure - Computation of Basic and Diluted Earnings Per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureComputationOfBasicAndDilutedEarningsPerShare</Role>
      <ShortName>Computation of Basic and Diluted Earnings Per Share (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>171 - Disclosure - Earnings (Loss) per Share - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureEarningsLossPerShareAdditionalInformation</Role>
      <ShortName>Earnings (Loss) per Share - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>172 - Disclosure - Capital Requirements and Restrictions on Retained Earnings - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureCapitalRequirementsAndRestrictionsOnRetainedEarningsAdditionalInformation</Role>
      <ShortName>Capital Requirements and Restrictions on Retained Earnings - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>173 - Disclosure - Ratios and Amounts of Tier One Capital and Total Capital to Risk-Adjusted Assets and Leverage Ratios (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureRatiosAndAmountsOfTierOneCapitalAndTotalCapitalToRiskAdjustedAssetsAndLeverageRatios</Role>
      <ShortName>Ratios and Amounts of Tier One Capital and Total Capital to Risk-Adjusted Assets and Leverage Ratios (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>174 - Disclosure - Consent Order to Achieve the Minimum Capital Ratios (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureConsentOrderToAchieveTheMinimumCapitalRatios</Role>
      <ShortName>Consent Order to Achieve the Minimum Capital Ratios (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>175 - Disclosure - Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pbibank.com/taxonomy/role/DisclosureContingenciesAdditionalInformation</Role>
      <ShortName>Contingencies - Additional Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Element pbib_InterestPayableAndOtherLiabilities had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element pbib_TroubledDebtRestructuringReserve had a mix of decimals attribute values: -5 0.</Log>
    <Log type="Info">Element us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets had a mix of decimals attribute values: 2 4.</Log>
    <Log type="Info">Element us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1 had a mix of decimals attribute values: -5 0.</Log>
    <Log type="Info">Element us-gaap_GainsLossesOnSalesOfOtherRealEstate had a mix of decimals attribute values: -3 0.</Log>
    <Log type="Info">Element us-gaap_LoansAndLeasesReceivableGrossCarryingAmount had a mix of decimals attribute values: -8 -5 -3 -2.</Log>
    <Log type="Info">Element us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets had a mix of decimals attribute values: 2 4.</Log>
    <Log type="Info">'Monetary' elements on report '104 - Statement - Consolidated Balance Sheets (Parenthetical)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '134 - Disclosure - Going Concern Considerations and Future Plans - Additional Information (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '142 - Disclosure - Balance in Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '151 - Disclosure - Net Activity Relating to Other Real Estate Owned Activity (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '159 - Disclosure - Fair Values Measurement - Additional Information (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '165 - Disclosure - Income Taxes - Additional Information (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '175 - Disclosure - Contingencies - Additional Information (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 103 - Statement - Consolidated Balance Sheets</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Mar. 31, 2013'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2012'</Log>
    <Log type="Info">Process Flow-Through: 104 - Statement - Consolidated Balance Sheets (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 105 - Statement - Consolidated Statements of Operations</Log>
    <Log type="Info">	Process Flow-Through: Removing column '12 Months Ended
Dec. 31, 2013'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '12 Months Ended
Dec. 31, 2012'</Log>
    <Log type="Info">Process Flow-Through: 106 - Statement - Consolidated Statements of Comprehensive Income (Loss)</Log>
    <Log type="Info">Process Flow-Through: 108 - Statement - Consolidated Statements of Cash Flows</Log>
  </Logs>
  <InputFiles>
    <File>pbib-20140331.xml</File>
    <File>pbib-20140331.xsd</File>
    <File>pbib-20140331_cal.xml</File>
    <File>pbib-20140331_def.xml</File>
    <File>pbib-20140331_lab.xml</File>
    <File>pbib-20140331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
