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Segments and Related Information (Narrative) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment and Related Information [Line Items]
Segment reporting information, factors used to identify entity's reportable segments									MasTec manages its operations under five operating segments, which represent MasTec’s five reportable segments: (1) Communications; (2) Oil and Gas; (3) Electrical Transmission; (4) Power Generation and Industrial and (5) Other. This structure is generally focused on broad end-user markets for MasTec’s labor-based construction services.
Number of operating segments \| segment									5
Number of reportable segments \| segment									5
Segment reporting information, description of products and services									All five reportable segments derive their revenue from the engineering, installation and maintenance of infrastructure, primarily in North America.
Segment reporting, description of all other segments									The Other segment includes equity investees, the services of which vary from those provided by the Company’s four primary segments, as well as other small business units that perform construction and other services for a variety of international end-markets.
Segment reporting, transactions between reportable segments									Intercompany revenue and costs among the reportable segments are de minimis and accounted for as if the sales were to third parties because these items are based on negotiated fees between the segments involved. All intercompany transactions and balances are eliminated in consolidation. Intercompany revenue and costs between entities within a reportable segment are eliminated to arrive at segment totals. Eliminations between segments are separately presented.
Segment reporting, additional information about entity's reportable segments									Segment results include certain allocations of centralized costs such as general liability, medical and workers’ compensation insurance and certain information technology costs. Income tax expense is managed by Corporate on a consolidated basis and is not allocated to the reportable segments.
Restructuring charges	$ 1,400	$ 4,700	$ 5,100	$ 4,100
Recognized unrealized loss, unconsolidated affiliates									$ (3,528)	$ 7,978	$ 269
Goodwill and intangible asset impairment									0	78,625	0
General and administrative expenses									$ 261,433	265,910	238,305
Corporate [Member]
Segment and Related Information [Line Items]
Goodwill and intangible asset impairment					$ 78,600					78,600
Corporate [Member] \| Audit Committee Investigation [Member]
Segment and Related Information [Line Items]
General and administrative expenses					2,800	$ 4,100	$ 7,500	$ 3,000		16,500
Canadian Dollars [Member] \| Pacer [Member]
Segment and Related Information [Line Items]
Goodwill and intangible asset impairment					78,600
Communications [Member]
Segment and Related Information [Line Items]
Segment reporting information, description of products and services									The Communications segment performs engineering, construction, maintenance and customer fulfillment activities related to communications infrastructure primarily for wireless and wireline/fiber communications and install-to-the-home customers, and, to a lesser extent, distribution infrastructure for electrical utilities, among others.
Business combinations, acquisition integration costs (in dollars)						1,200	$ 7,800	8,800		17,800	$ 5,300
Oil and Gas [Member]
Segment and Related Information [Line Items]
Segment reporting information, description of products and services									MasTec performs engineering, construction and maintenance services on oil and natural gas pipelines and processing facilities for the energy and utilities industries through its Oil and Gas segment.
Oil and Gas [Member] \| Canadian Dollars [Member]
Segment and Related Information [Line Items]
Restructuring charges									$ 6,300
Oil and Gas [Member] \| Canadian Dollars [Member] \| Contracts Accounted for under Percentage-of-Completion [Member]
Segment and Related Information [Line Items]
Project losses				13,500
Electrical Transmission [Member]
Segment and Related Information [Line Items]
Segment reporting information, description of products and services									The Electrical Transmission segment primarily serves the energy and utility industries through the engineering, construction and maintenance of electrical transmission lines and substations.
Restructuring charges									$ 8,900
Electrical Transmission [Member] \| Settled Litigation [Member]
Segment and Related Information [Line Items]
Court mandated mediation settlement charge						12,200				12,200
Electrical Transmission [Member] \| Contracts Accounted for under Percentage-of-Completion [Member]
Segment and Related Information [Line Items]
Project losses				$ 15,100						14,000
Power Generation and Industrial [Member]
Segment and Related Information [Line Items]
Segment reporting information, description of products and services									The Power Generation and Industrial segment primarily serves energy, utility and other end-markets through the installation and construction of conventional and renewable power facilities, related electrical transmission infrastructure, ethanol/biofuel facilities and various types of industrial infrastructure.
Power Generation and Industrial [Member] \| Canadian Dollars [Member] \| Contracts Accounted for under Percentage-of-Completion [Member]
Segment and Related Information [Line Items]
Project losses										21,400
Other [Member] \| Waha JVs [Member] \| Interest Rate Swap [Member]
Segment and Related Information [Line Items]
Recognized unrealized loss, unconsolidated affiliates					4,400					4,400
Other [Member] \| Canadian Dollars [Member] \| Contracts Accounted for under Percentage-of-Completion [Member] \| Pacer [Member] \| Joint Venture [Member]
Segment and Related Information [Line Items]
Project losses		$ 5,100			$ 8,000	$ 2,800		$ 5,500	$ 5,100	$ 16,300