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Note 7 - Commitments and Contingencies (Details Textual) $ in Millions | 1 Months Ended |  |  |
--- | --- | --- | --- | ---
Jan. 31, 2017 USD ($) | Jun. 30, 2025 USD ($) | Nov. 30, 2024 | Jun. 30, 2014 USD ($)
Letters of Credit Outstanding, Amount |  | $ 1.6 |  |
Portland Harbor Natural Resources Trustee Council [Member] |  |  |  |
Loss Contingency, Accrual, Current |  |  |  | $ 0.4
Portland Harbor Superfund Site [Member] |  |  |  |
Number Of Potentially Responsible Parties | 150 |  | 60 |
Estimated Cost of EPA Selected Remedy | $ 1,000.0 |  |  |
Estimated Time to Complete Selected EPA Remedy (Year) | 13 years |  |  |
Lower Willamette Group [Member] |  |  |  |
Number Of Potentially Responsible Parties | 14 |  |  |

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