Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets
Total current assets	$ 1,907,595	$ 1,852,366
Property and equipment, net	709,806	706,506
Goodwill and other intangible assets, net	1,332,900	1,328,900
Investments in and advances to consolidated affiliates, net	0	0
Other long-term assets	204,071	178,824
Total assets	4,154,348	4,066,576
Liabilities and equity
Total current liabilities	1,047,340	963,827
Long-term debt	1,343,549	1,280,706
Other long-term liabilities	389,300	388,700
Total liabilities	2,780,151	2,633,223
Total equity	1,374,197	1,433,353
Total liabilities and equity	4,154,348	4,066,576
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	1,356,000	1,415,000
Other long-term assets	15,700	15,800
Total assets	1,371,700	1,430,800
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	1,371,700	1,430,800
Total liabilities and equity	1,371,700	1,430,800
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Assets
Total current assets	1,641,500	1,536,600
Property and equipment, net	648,200	638,700
Goodwill and other intangible assets, net	1,195,600	1,187,900
Investments in and advances to consolidated affiliates, net	1,016,600	847,700
Other long-term assets	23,800	23,400
Total assets	4,525,700	4,234,300
Liabilities and equity
Total current liabilities	996,700	778,600
Long-term debt	1,336,000	1,269,400
Other long-term liabilities	380,400	379,900
Total liabilities	2,713,100	2,427,900
Total equity	1,812,600	1,806,400
Total liabilities and equity	4,525,700	4,234,300
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Assets
Total current assets	376,600	332,900
Property and equipment, net	61,600	67,800
Goodwill and other intangible assets, net	137,300	141,000
Investments in and advances to consolidated affiliates, net	702,500	746,600
Other long-term assets	164,500	139,600
Total assets	1,442,500	1,427,900
Liabilities and equity
Total current liabilities	161,100	202,300
Long-term debt	7,500	11,300
Other long-term liabilities	8,900	8,800
Total liabilities	177,500	222,400
Total equity	1,265,000	1,205,500
Total liabilities and equity	1,442,500	1,427,900
Eliminations [Member]
Assets
Total current assets	(110,500)	(17,100)
Property and equipment, net	0	0
Goodwill and other intangible assets, net	0	0
Investments in and advances to consolidated affiliates, net	(3,075,100)	(3,009,300)
Other long-term assets	0	0
Total assets	(3,185,600)	(3,026,400)
Liabilities and equity
Total current liabilities	(110,500)	(17,100)
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	(110,500)	(17,100)
Total equity	(3,075,100)	(3,009,300)
Total liabilities and equity	$ (3,185,600)	$ (3,026,400)