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Summary Of Significant Accounting Policies - Deferred Recertification And Dry Dock Costs (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items] |  |  |
Deferred recertification and dry dock costs, net | $ 21,464 | $ 16,065 |
Deferred recertification and dry dock costs accumulated amortization | 21,800 | 15,700 |
Recertification and dry dock amortization expense | $ 14,300 | $ 12,400 | $ 8,300
Minimum |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Recertification and dry dock amortization period | 30 months |  |
Recertification process period | 1 month |  |
Maximum |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Recertification and dry dock amortization period | 60 months |  |
Recertification process period | 3 months |  |

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- Definition Carrying amount of accumulated amortization of deferred recertification and dry dock costs at the end of the reporting period + References No definition available. + Details
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- Definition Deferred recertification and dry dock costs, Net + References No definition available. + Details
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- Definition Expense related to amortization of deferred recertification and dry dock costs + References No definition available. + Details
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Namespace Prefix: | hlx_
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- Definition The length of time in which the deferred recertification costs (including vessel dry dock costs) are amortized. + References No definition available. + Details
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- Definition The length of time to complete the recertification process (including vessel dry dock). + References No definition available. + Details
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