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v3.25.2

Revenue (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024 | Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |
Revenue, remaining performance obligation on dredging contracts | $ 960.4 |  | $ 960.4 |  |
Remaining performance obligations exclude from dredging backlog | 52.4 |  | 52.4 |  |
Performance obligations domestic low bids pending formal award and additional phases | $ 215.4 |  | $ 215.4 |  |
Percentage of performance obligation to be recognized as revenue |  |  | 40.00% |  |
Performance obligation, expected to be recognized as revenue year |  |  | 2025 |  |
Remaining performance obligation, expected timing of satisfaction, year | 2025 2026 |  | 2025 2026 |  |
Amortization on pre-construction costs | $ 5.8 | $ 4.0 | $ 9.2 | $ 8.4 |
Contracts and options pending award related to offshore wind contracts | 14.5 |  | 14.5 |  |
Other Current Assets [Member] |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |
Costs to fulfill contract customers recognized as asset | 8.3 |  | 8.3 |  | $ 10.3
Other Noncurrent Assets [Member] |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |
Costs to fulfill contract customers recognized as asset | $ 1.9 |  | $ 1.9 |  | $ 7.6

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