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Note 4 - Sale of Subsidiary (Details Textual) - USD ($) |  | 12 Months Ended
--- | --- | ---
Aug. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal |  | $ 0 | $ (14,539,000)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax |  | (0) | (13,083,000)
Financing Receivable, Allowance for Credit Loss |  | 914,000 | $ 900,000
Discontinued Operations, Disposed of by Sale [Member] | Subsidiary, Oil and Gas Product Manufacturing Operations in the Russian Federation [Member] |  |  |
Disposal Group, Including Discontinued Operation, Consideration | $ 1,000,000 |  |
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax | (13,100,000) |  |
Accounts and Financing Receivable, after Allowance for Credit Loss |  | $ 3,200,000 |
Discontinued Operations, Disposed of by Sale [Member] | Subsidiary, Oil and Gas Product Manufacturing Operations in the Russian Federation [Member] | Subsidiaries [Member] |  |  |
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal | (14,500,000) |  |
Discontinued Operations, Disposed of by Sale [Member] | Subsidiary, Oil and Gas Product Manufacturing Operations in the Russian Federation [Member] | Promissory Notes [Member] |  |  |
Disposal Group, Including Discontinued Operation, Consideration | $ 3,500,000 |  |
Notes Receivable, Term (Year) | 10 years |  |
Notes Receivable, Interest Rate, Stated Percentage | 5.00% |  |
Notes Receivable, Periodic Payment | $ 37,000 |  |
Financing Receivable, Allowance for Credit Loss | $ 900,000 |  |

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