Commitments and Contingencies (Other Guarantees) (Narrative) (Details)	9 Months Ended
Sep. 30, 2019
Minimum [Member]
Other Guarantees [Line Items]
General warranty, period (in years)	1 year
Maximum [Member]
Other Guarantees [Line Items]
General warranty, period (in years)	2 years

Period the Company generally warrants the work it performs following substantial completion of a project, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months and thirteen days.

No definition available.

Name:	mtz_WarrantyPeriodExpectedTerm
Namespace Prefix:	mtz_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration