XML 46 R38.htm IDEA: XBRL DOCUMENT
v3.25.1

Revenue (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Revenue, remaining performance obligation | $ 968.5 |  |
Performance obligations exclude from dredging backlog | 44.9 |  |
Performance obligations domestic low bids pending formal award and additional phases | $ 265.3 |  |
Percentage of performance obligation to be recognized as revenue | 60.00% |  |
Performance obligation, expected to be recognized as revenue year | 2025 |  |
Remaining performance obligation, expected timing of satisfaction, year | 2025 2026 |  |
Amortization on pre-construction costs | $ 3.4 | $ 4.4 |
Options pending award related to offshore wind contracts | 14.5 |  |
Other Current Assets [Member] |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Costs to fulfill contract customers recognized as asset | 12.3 |  | $ 10.3
Other Noncurrent Assets [Member] |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |
Costs to fulfill contract customers recognized as asset | $ 2.7 |  | $ 7.6

X
- Definition Options pending award offshore wind contracts. + References No definition available. + Details
Name: | gldd_OptionsPendingAwardOffshoreWindContracts
Namespace Prefix: | gldd_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of performance obligation to be recognized as revenue. + References No definition available. + Details
Name: | gldd_PercentageOfPerformanceObligationToBeRecognizedAsRevenue
Namespace Prefix: | gldd_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Performance obligation expected to be recognized as revenue, year. + References No definition available. + Details
Name: | gldd_PerformanceObligationExpectedToBeRecognizedAsRevenueYear
Namespace Prefix: | gldd_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Performance obligations domestic low bids pending formal award and additional phases. + References No definition available. + Details
Name: | gldd_PerformanceObligationsDomesticLowBidsPendingFormalAwardAndAdditionalPhases
Namespace Prefix: | gldd_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Performance obligations exclude from dredging backlog. + References No definition available. + Details
Name: | gldd_PerformanceObligationsExcludeFromDredgingBacklog
Namespace Prefix: | gldd_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 340 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479483/340-40-50-3 + Details
Name: | us-gaap_CapitalizedContractCostAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, before accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 340 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479483/340-40-50-3 + Details
Name: | us-gaap_CapitalizedContractCostGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of transaction price allocated to performance obligation that has not been recognized as revenue. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -SubTopic 10 -Topic 606 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-13 + Details
Name: | us-gaap_RevenueRemainingPerformanceObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Year in which remaining performance obligation is expected to be recognized, in YYYY format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b)(1) -SubTopic 10 -Topic 606 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-13 + Details
Name: | us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionYear1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:gYearListItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherCurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |