Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets
Current assets	$ 1,238,314	$ 1,531,751
Property and equipment, net	586,993	623,118
Goodwill and other intangible assets, net	1,283,600	1,332,800
Investments in and advances to consolidated affiliates, net	0	0
Other long-term assets	136,896	76,272
Total assets	3,245,786	3,563,980
Liabilities and equity
Total current liabilities	787,410	980,848
Long-term debt	1,098,585	1,061,159
Advances from consolidated affiliates, net		0
Other long-term liabilities	335,300	373,900
Total liabilities	2,221,302	2,415,905
Total equity	1,024,484	1,148,075
Total liabilities and equity	3,245,786	3,563,980
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	2,036,400	2,108,400
Other long-term assets	9,300	9,300
Total assets	2,045,700	2,117,700
Liabilities and equity
Total current liabilities	0	0
Long-term debt	0	0
Advances from consolidated affiliates, net		0
Other long-term liabilities	0	0
Total liabilities	0	0
Total equity	2,045,700	2,117,700
Total liabilities and equity	2,045,700	2,117,700
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Assets
Current assets	1,007,700	1,249,600
Property and equipment, net	464,900	472,600
Goodwill and other intangible assets, net	1,055,600	1,068,300
Investments in and advances to consolidated affiliates, net	95,700	0
Other long-term assets	38,700	28,700
Total assets	2,662,600	2,819,200
Liabilities and equity
Total current liabilities	666,600	777,400
Long-term debt	1,068,100	1,027,300
Advances from consolidated affiliates, net		70,700
Other long-term liabilities	227,400	239,300
Total liabilities	1,962,100	2,114,700
Total equity	700,500	704,500
Total liabilities and equity	2,662,600	2,819,200
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Assets
Current assets	230,600	282,200
Property and equipment, net	122,100	150,500
Goodwill and other intangible assets, net	228,000	264,500
Investments in and advances to consolidated affiliates, net	1,083,800	1,097,000
Other long-term assets	88,900	38,300
Total assets	1,753,400	1,832,500
Liabilities and equity
Total current liabilities	120,800	203,400
Long-term debt	30,500	33,900
Advances from consolidated affiliates, net		0
Other long-term liabilities	107,900	134,600
Total liabilities	259,200	371,900
Total equity	1,494,200	1,460,600
Total liabilities and equity	1,753,400	1,832,500
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	(3,215,900)	(3,205,400)
Other long-term assets	0	0
Total assets	(3,215,900)	(3,205,400)
Liabilities and equity
Total current liabilities	0	0
Long-term debt	0	0
Advances from consolidated affiliates, net		(70,700)
Other long-term liabilities	0	0
Total liabilities	0	(70,700)
Total equity	(3,215,900)	(3,134,700)
Total liabilities and equity	$ (3,215,900)	$ (3,205,400)