2.4.0.81085 - Disclosure - Pensions and Other Postretirement Benefits - Assumed Health Care Cost Trend Rates (Detail)truefalsefalse1false falsefalseeol_PE9760----1210-K0011_STD_366_20120831_0http://www.sec.gov/CIK0000739608duration2011-09-01T00:00:002012-08-31T00:00:00pureStandardhttp://www.xbrl.org/2003/instancepure02false falsefalseeol_PE9760----1210-K0011_STD_365_20110831_0http://www.sec.gov/CIK0000739608duration2010-09-01T00:00:002011-08-31T00:00:00pureStandardhttp://www.xbrl.org/2003/instancepure03false falsefalseeol_PE9760----1210-K0011_STD_365_20100831_0http://www.sec.gov/CIK0000739608duration2009-09-01T00:00:002010-08-31T00:00:00pureStandardhttp://www.xbrl.org/2003/instancepure01true 1us-gaap_CompensationAndRetirementDisclosureAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Compensation And Retirement Disclosure [Abstract]2false 2us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.08000.0800falsefalsefalse2truetruefalse0.08000.0800falsefalsefalse3truetruefalse0.08000.0800falsefalsefalsenum:percentItemTypepureThe assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph l -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Health Care Cost Trend Rate -URI http://asc.fasb.org/extlink&oid=6514820 false0Current health care trend assumption3false 2us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRateus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.04500.0450falsefalsefalse2truetruefalse0.04500.0450falsefalsefalse3truetruefalse0.04500.0450falsefalsefalsenum:percentItemTypepureThe ultimate trend rate for health care costs.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph l -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Ultimate health care trend rate4false 2us-gaap_DefinedBenefitPlanYearThatRateReachesUltimateTrendRateus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse002030falsefalsefalse2falsefalsefalse002029falsefalsefalse3falsefalsefalse002028falsefalsefalsexbrli:gYearItemTypepositiveintegerYear the ultimate health care cost trend rate is expected to be reached, in CCYY format.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph l -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Year ultimate health care trend is reachedfalsePensions and Other Postretirement Benefits - Assumed Health Care Cost Trend Rates (Detail)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.penx.com/taxonomy/role/DisclosurePensionsAndOtherPostretirementBenefitsAssumedHealthCareCostTrendRates34