XML 36 R21.htm IDEA: XBRL DOCUMENT v2.4.0.6

Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 plan claim
Commitments and Contingencies
Number of multi-employer pension plans, the withdrawal of which could result in assessment of liabilities for additional contributions related to the underfunding of plans, minimum	1
Potential number of litigation claims in which an adverse outcome could result, minimum	1
Insurance and Claims Accruals
Commitments and Contingencies
Deductible per claim, once a policy's claim aggregate is reached per line of coverage	1.0
Deductible under health insurance benefits for qualified individuals	0.1
Insurance and Claims Accruals | Minimum
Commitments and Contingencies
Deductible per claim for each line of coverage, until claim aggregate is reached	1.0
Insurance and Claims Accruals | Maximum
Commitments and Contingencies
Deductible per claim for each line of coverage, until claim aggregate is reached	1.5
Surety bonds
Commitments and Contingencies
Aggregate original face amount of outstanding bonds issued by the surety	914.1
Estimated remaining cost to complete bonded projects	351.4

X

- Definition

Represents the amount of deductible under health insurance benefits for qualified individuals.

+ References

No definition available.

+ Details

Name:	myrg_LossContingencyHealthInsuranceDeductibleForQualifiedIndividuals
Namespace Prefix:	myrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Represents the amount of deductible up to the claim aggregate under insurance arrangements, for each line of coverage excluding medical insurance.

+ References

No definition available.

+ Details

Name:	myrg_LossContingencyInsurancePolicyDeductibleForEachLineOfCoverage
Namespace Prefix:	myrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Represents the amount of deductible under insurance arrangements, once the policy's claim aggregate is reached for each line of coverage, excluding medical insurance.

+ References

No definition available.

+ Details

Name:	myrg_LossContingencyInsurancePolicyDeductibleIfClaimAggregateReachedPerLineOfCoverage
Namespace Prefix:	myrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Represents the minimum number of multi-employer pension plans from the withdrawal of which a subsidiary could be assessed for liabilities for additional contributions related to the underfunding of plans.

+ References

No definition available.

+ Details

Name:	myrg_NumberOfMultiemployerPlansWithdrawalThatCouldResultInAssessmentOfAdditionalContributionLiabilitiesRelatedToUnderfundingOfPlansMinimum
Namespace Prefix:	myrg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the minimum potential number of litigation claims in which an adverse outcome could result.

+ References

No definition available.

+ Details

Name:	myrg_PotentialAdverseOutcomeNumberOfLitigationClaimsMinimum
Namespace Prefix:	myrg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Definition

The estimated maximum amount of possible loss from the contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14557-108349



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 14

-Paragraph 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

+ Details

Name:	us-gaap_LossContingencyRangeOfPossibleLossMaximum
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 14

-Paragraph 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_LossContingencyRangeOfPossibleLossPortionNotAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant