XML 83 R70.htm IDEA: XBRL DOCUMENT v3.24.0.1

Retirement Plans (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Item	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Number of sponsored 401(k) plans | Item	2
Expense for matching and discretionary contributions	$ 4,757	$ 2,996	$ 4,659
Contributes to various multiemployer pension plans	$ 5,153	$ 4,915	$ 4,632
Maximum [Member]
Defined Contribution Plan Disclosure [Line Items]
Multiemployer plans collective-bargaining arrangement percentage of contributions	5.00%

X

- Definition

Number of sponsored 401(k) plans

+ References

No definition available.

+ Details

Name:	gldd_NumberOfSponsored401KPlans
Namespace Prefix:	gldd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

+ Details

Name:	us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Percentage of employer contribution required by collective-bargaining arrangement (CBA) to total contribution from all participating employers in multiemployer pension plan determined to be individually significant.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

+ Details

Name:	us-gaap_MultiemployerPlanPensionSignificantEmployerContributionUnderCollectiveBargainingArrangementToAllParticipatingEmployerContributionsPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: