| Note 5 - Goodwill and Other Intangible Assets (Details) - Changes in the Carrying Amount Goodwill by Reporting Segments (USD $) | 12 Months Ended | 0 Months Ended | ||
|---|---|---|---|---|
| Dec. 31, 2014 | Dec. 31, 2013 | Oct. 01, 2014 | Oct. 01, 2013 | |
| Goodwill [Line Items] | ||||
| Balance | $ 1,330,000us-gaap_Goodwill | $ 29,186,000us-gaap_Goodwill | ||
| Goodwill impairment | (380,000)us-gaap_GoodwillImpairmentLoss | (27,856,000)us-gaap_GoodwillImpairmentLoss | ||
| Balance | 0us-gaap_Goodwill | 1,330,000us-gaap_Goodwill | ||
| Treatment [Member] | ||||
| Goodwill [Line Items] | ||||
| Balance | 13,691,000us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pesi_TreatmentMember | |||
| Goodwill impairment | (13,691,000)us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = pesi_TreatmentMember | 0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = pesi_TreatmentMember | 0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = pesi_TreatmentMember | |
| Services [Member] | SYA [Member] | ||||
| Goodwill [Line Items] | ||||
| Sale of SYA subsidary | (950,000)us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = pesi_SYAMember / us-gaap_StatementBusinessSegmentsAxis = pesi_ServicesMember | |||
| Services [Member] | ||||
| Goodwill [Line Items] | ||||
| Balance | 1,330,000us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pesi_ServicesMember | 15,495,000us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pesi_ServicesMember | ||
| Goodwill impairment | (380,000)us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = pesi_ServicesMember | (14,165,000)us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = pesi_ServicesMember | ||
| Balance | 1,330,000us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pesi_ServicesMember | |||
| SYA [Member] | ||||
| Goodwill [Line Items] | ||||
| Sale of SYA subsidary | $ (950,000)us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = pesi_SYAMember | |||
| X | ||||||||||
| 
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Definition Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |