2.4.0.82401406 - Disclosure - Summary of Significant Accounting Policies - Debt Issuance Cost and Debt Discounts (Details)truefalseIn Millions, unless otherwise specifiedfalse1false USDfalsefalse$D2012Q4YTDhttp://www.sec.gov/CIK0000356213duration2012-01-01T00:00:002012-12-31T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$D2011Q4YTDhttp://www.sec.gov/CIK0000356213duration2011-01-01T00:00:002011-12-31T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$D2010Q4YTDhttp://www.sec.gov/CIK0000356213duration2010-01-01T00:00:002010-12-31T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 1us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Organization, Consolidation and Presentation of Financial Statements [Abstract]2false 2us-gaap_UnamortizedDebtIssuanceExpenseus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse3430000034.3USD$falsetruefalse2truefalsefalse3120000031.2USD$falsetruefalse3falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false2Unamortized debt issuance costs3false 2us-gaap_AmortizationOfFinancingCostsus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse65000006.5USD$falsetruefalse2truefalsefalse52000005.2USD$falsetruefalse3truefalsefalse67000006.7USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 8 -Article 9 false2Amortization of debt issuance costs and debt discountsfalseSummary of Significant Accounting Policies - Debt Issuance Cost and Debt Discounts (Details) (USD $)HundredThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.pnkinc.com/role/SummaryOfSignificantAccountingPoliciesDebtIssuanceCostAndDebtDiscountsDetails33