<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xml:lang="en-US"
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2020-01-31"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="hlx-20210222.xsd" xlink:type="simple"/>
    <context id="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000866829</identifier>
        </entity>
        <period>
            <startDate>2021-02-22</startDate>
            <endDate>2021-02-22</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV80L2ZyYWc6Njc0NDZhMTlmMmUyNGUxZjhmZWJjZWYzM2YyNmNhM2MvdGFibGU6NjFiYjQ2MzA3NjM5NDMxMGJkYTNkMzNmNGUxZWQ1NWMvdGFibGVyYW5nZTo2MWJiNDYzMDc2Mzk0MzEwYmRhM2QzM2Y0ZTFlZDU1Y18yLTEtMS0xLTA_33931fa2-1418-4812-a2f5-95cc94c8947b">0000866829</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV80L2ZyYWc6Njc0NDZhMTlmMmUyNGUxZjhmZWJjZWYzM2YyNmNhM2MvdGFibGU6NjFiYjQ2MzA3NjM5NDMxMGJkYTNkMzNmNGUxZWQ1NWMvdGFibGVyYW5nZTo2MWJiNDYzMDc2Mzk0MzEwYmRhM2QzM2Y0ZTFlZDU1Y18zLTEtMS0xLTA_ea69d40c-0535-400d-a871-38c9c6611d58">false</dei:AmendmentFlag>
    <dei:DocumentType
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjQ2_c1b5c1a3-e4c5-4ff0-a1d2-edf8cfd067d5">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18yMzY_cd1017c2-f9a2-47ef-9446-f8e21307d4d5">2021-02-22</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjQ3_cdacd110-1962-4249-959f-959b920012b5">HELIX ENERGY SOLUTIONS GROUP, INC.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl8wLTAtMS0xLTA_9a9a4aa0-191e-4162-8f52-3310c7f78174">MN</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl8wLTItMS0xLTA_69894bcb-258c-491d-a07c-94a7f538782f">001-32936</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl8wLTQtMS0xLTA_4b8b8d4f-d1ae-44b9-a7d4-189f81bfaf1b">95-3409686</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl8zLTAtMS0xLTA_ec526154-6b4c-47a9-baaf-3e6e39e516b2">3505 West Sam Houston Parkway North</dei:EntityAddressAddressLine1>
    <dei:EntityAddressAddressLine2
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl80LTAtMS0xLTA_b9a515a6-63b3-4b98-a9e7-2da6a9ba5012">Suite 400</dei:EntityAddressAddressLine2>
    <dei:EntityAddressCityOrTown
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl81LTAtMS0xLTA_5c3f3559-0859-4657-b025-27bdb0b9fbd6">Houston,</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl81LTEtMS0xLTA_9ea4d72e-664e-4cf7-b35e-efd92541054a">TX</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6OTNkMjFkZmI0OTM4NGM0YTkzZGRhMjVkYjRlNmQwMjYvdGFibGVyYW5nZTo5M2QyMWRmYjQ5Mzg0YzRhOTNkZGEyNWRiNGU2ZDAyNl81LTMtMS0xLTA_4ec9570a-8bd9-4e6c-8048-a30161e235a7">77043</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjUw_50af3d0c-acfb-41e2-b4ee-58ecd9691228">281</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjQ4_b301c234-622f-4c33-a000-ca58ab5ed175">618-0400</dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjQ5_683acf2b-6a3e-4624-9020-0ad07ca8c405">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjUx_68d634c4-0b35-41e4-bd87-2441f4f5b130">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjQ0_e121c1dc-a3ef-4185-be2e-591ba68fc7e2">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjUy_6c69b8ef-fdb1-4fbf-ad8a-323da7d4d391">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6NDdlY2M1YzE5NDlkNDkxMGI0NmJiOGU0Y2Q5MjVlYTcvdGFibGVyYW5nZTo0N2VjYzVjMTk0OWQ0OTEwYjQ2YmI4ZTRjZDkyNWVhN18xLTAtMS0xLTA_d915a1ca-6424-4c2d-a4d6-d921fae0c133">Common Stock</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6NDdlY2M1YzE5NDlkNDkxMGI0NmJiOGU0Y2Q5MjVlYTcvdGFibGVyYW5nZTo0N2VjYzVjMTk0OWQ0OTEwYjQ2YmI4ZTRjZDkyNWVhN18xLTItMS0xLTA_d5e885a6-e5b1-4420-a317-08b50556b11f">HLX</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGFibGU6NDdlY2M1YzE5NDlkNDkxMGI0NmJiOGU0Y2Q5MjVlYTcvdGFibGVyYW5nZTo0N2VjYzVjMTk0OWQ0OTEwYjQ2YmI4ZTRjZDkyNWVhN18xLTQtMS0xLTA_c697bcbe-4b5a-4f46-b9e2-30b089828e43">NYSE</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="ibd759c12a96f44acb9f8cabe3bfb04da_D20210222-20210222"
      id="id3VybDovL2RvY3MudjEvZG9jOjJkYmUxMGE5MDNjNjRkNmRhZDJhNTEzMGIwZGE1NjQxL3NlYzoyZGJlMTBhOTAzYzY0ZDZkYWQyYTUxMzBiMGRhNTY0MV8xL2ZyYWc6MzdjZGEwMDY0MmVhNGIxNWJhZWZhYWU5YTkyZmNiOTcvdGV4dHJlZ2lvbjozN2NkYTAwNjQyZWE0YjE1YmFlZmFhZTlhOTJmY2I5N18xNjQ1_d0f8e831-62c0-49c5-a4de-dd1a30e10dcc">false</dei:EntityEmergingGrowthCompany>
</xbrl>
