Supplemental Guarantor Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Total current assets	$ 1,852,366	$ 1,402,486
Property and equipment, net	706,506	549,084
Goodwill and other intangible assets, net	1,328,900	1,175,600
Investments in and advances to consolidated affiliates, net	0	0
Other long-term assets	178,824	55,977
Total assets	4,066,576	3,183,132	$ 2,927,300
Liabilities and equity
Total current liabilities	963,827	839,990
Long-term debt	1,280,706	961,379
Other long-term liabilities	388,700	278,100
Total liabilities	2,633,223	2,079,498
Total equity	1,433,353	1,103,634	$ 943,391	$ 1,148,075
Total liabilities and equity	4,066,576	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	1,415,000	1,083,900
Other long-term assets	15,800	12,600
Total assets	1,430,800	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	1,430,800	1,096,500
Total liabilities and equity	1,430,800	1,096,500
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Assets
Total current assets	1,536,600	1,257,200
Property and equipment, net	638,700	463,700
Goodwill and other intangible assets, net	1,187,900	1,037,400
Investments in and advances to consolidated affiliates, net	847,700	617,400
Other long-term assets	23,400	25,200
Total assets	4,234,300	3,400,900
Liabilities and equity
Total current liabilities	778,600	742,800
Long-term debt	1,269,400	941,700
Other long-term liabilities	379,900	258,100
Total liabilities	2,427,900	1,942,600
Total equity	1,806,400	1,458,300
Total liabilities and equity	4,234,300	3,400,900
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Assets
Total current assets	332,900	155,500
Property and equipment, net	67,800	85,400
Goodwill and other intangible assets, net	141,000	138,200
Investments in and advances to consolidated affiliates, net	746,600	867,700
Other long-term assets	139,600	18,100
Total assets	1,427,900	1,264,900
Liabilities and equity
Total current liabilities	202,300	107,400
Long-term debt	11,300	19,700
Other long-term liabilities	8,800	20,000
Total liabilities	222,400	147,100
Total equity	1,205,500	1,117,800
Total liabilities and equity	1,427,900	1,264,900
Eliminations [Member]
Assets
Total current assets	(17,100)	(10,200)
Property and equipment, net	0	0
Goodwill and other intangible assets, net	0	0
Investments in and advances to consolidated affiliates, net	(3,009,300)	(2,569,000)
Other long-term assets	0	0
Total assets	(3,026,400)	(2,579,200)
Liabilities and equity
Total current liabilities	(17,100)	(10,200)
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	(17,100)	(10,200)
Total equity	(3,009,300)	(2,569,000)
Total liabilities and equity	$ (3,026,400)	$ (2,579,200)