XML 37 R89.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Employee Benefit Plans - Summary of multi-employer benefit plans (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Significant multiemployer plans |  |  |
Contributions to Plan | $ 102,209 | $ 70,420 | $ 64,888
Multiemployer Plans, Pension [Member] | Southern California IBEW-NECA Pension Trust Fund [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 14,268 | 767 | 435
Multiemployer Plans, Pension [Member] | National Electrical Benefit Fund [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 11,050 | 9,840 | 9,542
Multiemployer Plans, Pension [Member] | Eighth District Electrical Pension Fund [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 11,199 | 9,707 | 7,908
Multiemployer Plans, Pension [Member] | IBEW Local 769 Management Pension Plan A [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 2,689 | 2,587 | 2,115
Multiemployer Plans, Pension [Member] | IBEW Local No. 640 and Arizona NECA Defined Benefit Pension Plan [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 2,397 | 1,629 | 0
Multiemployer Plans, Pension [Member] | Indiana/Kentucky/Ohio Regional Council of Carpenters Pension Fund [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 1,742 | 1,157 | 2,515
Multiemployer Plans, Pension [Member] | Alaska Electrical Pension Plan [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 1,408 | 2,723 | 1,951
Multiemployer Plans, Postretirement Benefit [Member] | National Electrical Annuity Plan [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 28,822 | 26,559 | 27,633
Multiemployer Plans, Postretirement Benefit [Member] | Eighth District Electrical Pension Fund Annuity Plan [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | 5,339 | 4,785 | 4,109
Multiemployer Plans Other Pension Post Retirement And Supplemental Plans [Member] | All other plans [Member] |  |  |
Significant multiemployer plans |  |  |
Contributions to Plan | $ 23,295 | $ 10,666 | $ 8,680

X
- Definition Amount of contributions made to multiemployer plan by employer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
Name: | us-gaap_MultiemployerPlanContributionsByEmployer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Details
Name: | us-gaap_MultiemployerPlanTypeAxis=us-gaap_MultiemployerPlansPensionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_SouthernCaliforniaIbewNecaPensionTrustFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_NationalElectricalBenefitFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_EighthDistrictElectricalPensionFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_IbewLocal769ManagementPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_IbewLocalNo.640AndArizonaNecaDefinedBenefitPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_IndianaKentuckyOhioRegionalCouncilOfCarpentersPensionFundMemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_AlaskaElectricalPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanTypeAxis=us-gaap_MultiemployerPlansPostretirementBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_NationalElectricalAnnuityPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_EighthDistrictElectricalPensionFundAnnuityPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanTypeAxis=myrg_MultiemployerPlansOtherPensionPostRetirementAndSupplementalPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MultiemployerPlanNameAxis=myrg_AllOtherPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |