Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Total current assets	$ 1,747,747	$ 1,402,486
Property and equipment, net	691,430	549,084
Goodwill and other intangible assets, net	1,330,900	1,175,600
Investments in and advances to consolidated affiliates, net	0	0
Other long-term assets	172,094	55,977
Total assets	3,942,175	3,183,132
Liabilities and equity
Total current liabilities	1,002,151	839,990
Long-term debt	1,192,311	961,379
Other long-term liabilities	444,700	278,100
Total liabilities	2,639,130	2,079,498
Total equity	1,303,045	1,103,634
Total liabilities and equity	3,942,175	3,183,132
Reportable Legal Entities [Member] | MasTec, Inc. [Member]
Assets
Total 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	1,279,700	1,083,900
Other long-term assets	15,800	12,600
Total assets	1,295,500	1,096,500
Liabilities and equity
Total current liabilities	0	0
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	0	0
Total equity	1,295,500	1,096,500
Total liabilities and equity	1,295,500	1,096,500
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Assets
Total current assets	1,576,000	1,256,300
Property and equipment, net	600,800	456,600
Goodwill and other intangible assets, net	1,187,900	1,037,400
Investments in and advances to consolidated affiliates, net	848,000	625,900
Other long-term assets	25,700	25,300
Total assets	4,238,400	3,401,500
Liabilities and equity
Total current liabilities	982,500	759,700
Long-term debt	1,181,100	938,700
Other long-term liabilities	432,000	256,200
Total liabilities	2,595,600	1,954,600
Total equity	1,642,800	1,446,900
Total liabilities and equity	4,238,400	3,401,500
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Assets
Total current assets	259,800	175,800
Property and equipment, net	90,600	92,500
Goodwill and other intangible assets, net	143,000	138,200
Investments in and advances to consolidated affiliates, net	710,200	861,200
Other long-term assets	130,600	18,000
Total assets	1,334,200	1,285,700
Liabilities and equity
Total current liabilities	107,700	109,900
Long-term debt	11,200	22,700
Other long-term liabilities	12,700	21,900
Total liabilities	131,600	154,500
Total equity	1,202,600	1,131,200
Total liabilities and equity	1,334,200	1,285,700
Eliminations [Member]
Assets
Total current assets	(88,100)	(29,600)
Property and equipment, net	0	0
Goodwill and other intangible assets, net	0	0
Investments in and advances to consolidated affiliates, net	(2,837,900)	(2,571,000)
Other long-term assets	0	0
Total assets	(2,926,000)	(2,600,600)
Liabilities and equity
Total current liabilities	(88,100)	(29,600)
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	(88,100)	(29,600)
Total equity	(2,837,900)	(2,571,000)
Total liabilities and equity	$ (2,926,000)	$ (2,600,600)