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Note 11 - Segment Information (Details Textual) - Operating Segments [Member] - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
Water Transmission Systems [Member[] |  |  |  |
Cost, Depreciation, Amortization and Depletion | $ 2.9 | $ 3.0 | $ 5.4 | $ 5.7
Precast Infrastructure and Engineered Systems [Member] |  |  |  |
Cost, Depreciation, Amortization and Depletion | $ 0.8 | $ 0.7 | $ 1.6 | $ 1.2

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