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Amount of accumulated amortization of asset recognized from cost incurred to obtain or fulfill contract with customer.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

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Revenue (Narrative) (Details) - USD ($)	12 Months Ended
Revenue (Narrative) (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Performance obligations exclude from dredging backlog	$ 44,600,000
Revenue, remaining performance obligation	$ 1,040,000,000.00
Percentage of performance obligation to be recognized as revenue	60.00%
Performance obligation, expected to be recognized as revenue year	2024
Amortization on pre-contract and pre-construction costs	$ 11,474,000	$ 11,148,000
Contract revenues	589,625,000	648,781,000	$ 726,149,000
Long-lived assets, net book value	$ 0	0
Increased gross profit		$ 22,276,000
Dredging [Member] \| Use of Equipment [Member] \| Federal Government [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Contract revenues			$ 716,000
Dredging [Member] \| Sales [Member] \| Geographic Concentration Risk [Member] \| Middle East [Member] \| Maximum [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	1.00%	1.00%	1.00%
Dredging [Member] \| Sales [Member] \| Federal Government Agencies [Member] \| Customer Concentration Risk [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	75.00%	67.00%	78.00%
Dredging [Member] \| Accounts Receivable [Member] \| Geographic Concentration Risk [Member] \| Middle East [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	0.00%	9.00%
Dredging [Member] \| Accounts Receivable [Member] \| Federal Government Agencies [Member] \| Customer Concentration Risk [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	36.00%	46.00%
Other Current Assets [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Costs to fulfill contracts with customers recognized as an asset	$ 18,138,000	$ 4,472,000
Other Noncurrent Assets [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Costs to fulfill contracts with customers recognized as an asset	$ 4,028,000	$ 0