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Earnings Per Share - (Narrative) (Details) shares in Thousands | 3 Months Ended
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Mar. 31, 2023 shares
Earnings Per Share [Abstract] |
Stock options and restricted stock units excluded from weighted-average common shares outstanding | 246

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- Definition Antidilutive securities excluded from diluted weighted-average common shares outstanding. + References No definition available. + Details
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Namespace Prefix: | gldd_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_EarningsPerShareAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration