| Note 17 - Segment Reporting (Details) (USD $)
 | 0 Months Ended | 12 Months Ended | 0 Months Ended | 3 Months Ended | 
| Aug. 02, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Jul. 29, 2014 | Oct. 01, 2014 | Oct. 01, 2013 | Sep. 30, 2014 | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Number of Reportable Segments |  | 2us-gaap_NumberOfReportableSegments |  |  |  |  |  |  |  | 
| Disposal Group, Including Discontinued Operation, Assets, Including Not Held for Sale |  | $ 701,000pesi_AssetsOfDisposalGroupIncludingDiscontinuedOperationIncludingNotHeldForSale |  | $ 4,481,000pesi_AssetsOfDisposalGroupIncludingDiscontinuedOperationIncludingNotHeldForSale |  |  |  |  |  | 
| Assets |  | 88,636,000us-gaap_Assets | [1] | 92,060,000us-gaap_Assets | [1] |  |  |  |  | 
| Debt Instrument, Unamortized Discount |  | 137,000us-gaap_DebtInstrumentUnamortizedDiscount |  | 223,000us-gaap_DebtInstrumentUnamortizedDiscount |  |  |  |  |  | 
| Debt Conversion, Converted Instrument, Warrants or Options Issued (in Shares) | 2us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1 |  |  |  |  |  |  |  |  | 
| Stock Issued as Consideration for Debt (in Shares) | 90,000pesi_StockIssuedAsConsiderationForDebt |  |  |  |  |  |  |  |  | 
| Debt Instrument, Face Amount | 3,000,000us-gaap_DebtInstrumentFaceAmount |  |  |  |  |  |  |  |  | 
| Goodwill, Impairment Loss |  | 380,000us-gaap_GoodwillImpairmentLoss |  | 27,856,000us-gaap_GoodwillImpairmentLoss |  |  |  |  |  | 
| USEC [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Revenues |  | 10,272,000us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis
 = pesi_USECMember
 |  | 2,037,000us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis
 = pesi_USECMember
 |  |  |  |  |  | 
| Concentration Risk, Percentage |  | 18.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_StatementBusinessSegmentsAxis
 = pesi_USECMember
 |  | 2.70%us-gaap_ConcentrationRiskPercentage1 / us-gaap_StatementBusinessSegmentsAxis
 = pesi_USECMember
 |  |  |  |  |  | 
| CH Plateau Remediation Company [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Revenues |  | 5,762,000us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis
 = pesi_CHPlateauRemediationCompanyMember
 |  | 19,922,000us-gaap_Revenues / us-gaap_StatementBusinessSegmentsAxis
 = pesi_CHPlateauRemediationCompanyMember
 |  |  |  |  |  | 
| Concentration Risk, Percentage |  | 10.10%us-gaap_ConcentrationRiskPercentage1 / us-gaap_StatementBusinessSegmentsAxis
 = pesi_CHPlateauRemediationCompanyMember
 |  | 26.80%us-gaap_ConcentrationRiskPercentage1 / us-gaap_StatementBusinessSegmentsAxis
 = pesi_CHPlateauRemediationCompanyMember
 |  |  |  |  |  | 
| Services [Member] | SYA [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Goodwill, Impairment Loss |  |  |  |  |  | 380,000us-gaap_GoodwillImpairmentLoss / dei_LegalEntityAxis
 = pesi_SYAMember
 / us-gaap_StatementBusinessSegmentsAxis
 = pesi_ServicesMember
 |  |  |  | 
| Services [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Assets |  | 8,920,000us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis
 = pesi_ServicesMember
 | [1] | 11,951,000us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis
 = pesi_ServicesMember
 | [1] |  |  |  |  | 
| Goodwill, Impairment Loss |  | 380,000us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis
 = pesi_ServicesMember
 |  | 14,165,000us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis
 = pesi_ServicesMember
 |  |  |  |  |  | 
| Treatment [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Assets |  | 50,226,000us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis
 = pesi_TreatmentMember
 | [1] | 49,978,000us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis
 = pesi_TreatmentMember
 | [1] |  |  |  |  | 
| Goodwill, Impairment Loss |  |  |  | 13,691,000us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis
 = pesi_TreatmentMember
 |  |  | 0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis
 = pesi_TreatmentMember
 | 0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis
 = pesi_TreatmentMember
 |  | 
| PF Medical S.A. [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Assets |  | 1,213,000us-gaap_Assets / dei_LegalEntityAxis
 = pesi_PFMedicalSAMember
 |  | 0us-gaap_Assets / dei_LegalEntityAxis
 = pesi_PFMedicalSAMember
 |  |  |  |  |  | 
| SYA [Member] |  |  |  |  |  |  |  |  |  | 
| Note 17 - Segment Reporting (Details) [Line Items] |  |  |  |  |  |  |  |  |  | 
| Goodwill, Impairment Loss |  |  |  |  |  | $ 380,000us-gaap_GoodwillImpairmentLoss / dei_LegalEntityAxis
 = pesi_SYAMember
 |  |  | $ 380,000us-gaap_GoodwillImpairmentLoss / dei_LegalEntityAxis
 = pesi_SYAMember
 | 
|  | 
|  |