Supplemental Guarantor Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets
Current assets	$ 1,531,751	$ 1,569,727	$ 1,482,610	$ 1,349,995	$ 1,307,026
Property and equipment, net	623,118	614,359	618,672	509,585	488,132
Goodwill and other intangible assets, net	1,332,800				1,067,700
Investments in and advances to consolidated affiliates, net	0				0
Other long-term assets	76,272	59,579	73,821	61,439	60,390
Total assets	3,563,980	3,465,901	3,388,828	3,005,466	2,923,198	$ 2,416,300
Liabilities and equity
Total current liabilities	980,848	905,196	863,687	823,181	829,225
Long-term debt	1,061,159	1,088,289	1,088,666	841,335	765,425
Advances from consolidated affiliates, net	0				0
Other long-term liabilities	373,900				307,500
Total liabilities	2,415,905	2,335,561	2,299,769	1,972,546	1,902,140
Total equity	1,148,075	1,130,340	1,089,059	1,032,920	1,021,058	$ 861,875	$ 811,207
Total liabilities and equity	3,563,980	$ 3,465,901	$ 3,388,828	$ 3,005,466	2,923,198
Reportable Legal Entities [Member] | MasTec, Inc. [Member]
Assets
Current assets	0				0
Property and equipment, net	0				0
Goodwill and other intangible assets, net	0				0
Investments in and advances to consolidated affiliates, net	2,108,400				1,006,800
Other long-term assets	9,300				9,300
Total assets	2,117,700				1,016,100
Liabilities and equity
Total current liabilities	0				0
Long-term debt	0				0
Advances from consolidated affiliates, net	0				0
Other long-term liabilities	0				0
Total liabilities	0				0
Total equity	2,117,700				1,016,100
Total liabilities and equity	2,117,700				1,016,100
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Assets
Current assets	1,249,600				1,156,700
Property and equipment, net	472,600				420,200
Goodwill and other intangible assets, net	1,068,300				932,800
Investments in and advances to consolidated affiliates, net	0				170,800
Other long-term assets	28,700				36,200
Total assets	2,819,200				2,716,700
Liabilities and equity
Total current liabilities	777,400				773,300
Long-term debt	1,027,300				760,900
Advances from consolidated affiliates, net	70,700				0
Other long-term liabilities	239,300				236,400
Total liabilities	2,114,700				1,770,600
Total equity	704,500				946,100
Total liabilities and equity	2,819,200				2,716,700
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Assets
Current assets	282,200				150,300
Property and equipment, net	150,500				67,900
Goodwill and other intangible assets, net	264,500				134,900
Investments in and advances to consolidated affiliates, net	1,097,000				0
Other long-term assets	38,300				14,900
Total assets	1,832,500				368,000
Liabilities and equity
Total current liabilities	203,400				55,900
Long-term debt	33,900				4,500
Advances from consolidated affiliates, net	0				22,500
Other long-term liabilities	134,600				71,100
Total liabilities	371,900				154,000
Total equity	1,460,600				214,000
Total liabilities and equity	1,832,500				368,000
Eliminations [Member]
Assets
Current assets	0				0
Property and equipment, net	0				0
Goodwill and other intangible assets, net	0				0
Investments in and advances to consolidated affiliates, net	(3,205,400)				(1,177,600)
Other long-term assets	0				0
Total assets	(3,205,400)				(1,177,600)
Liabilities and equity
Total current liabilities	0				0
Long-term debt	0				0
Advances from consolidated affiliates, net	(70,700)				(22,500)
Other long-term liabilities	0				0
Total liabilities	(70,700)				(22,500)
Total equity	(3,134,700)				(1,155,100)
Total liabilities and equity	$ (3,205,400)				$ (1,177,600)