Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets
Total current assets	$ 2,281,770	$ 1,852,366
Property and equipment, net	739,425	706,506
Goodwill and other intangible assets, net	1,328,100	1,328,900
Investments in and advances to consolidated affiliates, net	0	0
Other long-term assets	232,848	178,824
Total assets	4,582,157	4,066,576
Liabilities and equity
Total current liabilities	1,252,777	963,827
Long-term debt	1,532,978	1,280,706
Other long-term liabilities	366,000	388,700
Total liabilities	3,151,759	2,633,223
Total equity	1,430,398	1,433,353
Total liabilities and equity	4,582,157	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	1,411,800	1,415,000
Other long-term assets	16,300	15,800
Total assets	1,428,100	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	1,428,100	1,430,800
Total liabilities and equity	1,428,100	1,430,800
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Assets
Total current assets	2,125,900	1,536,600
Property and equipment, net	687,700	638,700
Goodwill and other intangible assets, net	1,193,700	1,187,900
Investments in and advances to consolidated affiliates, net	928,100	847,700
Other long-term assets	34,700	23,400
Total assets	4,970,100	4,234,300
Liabilities and equity
Total current liabilities	1,200,600	778,600
Long-term debt	1,522,900	1,269,400
Other long-term liabilities	352,900	379,900
Total liabilities	3,076,400	2,427,900
Total equity	1,893,700	1,806,400
Total liabilities and equity	4,970,100	4,234,300
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Assets
Total current assets	270,400	332,900
Property and equipment, net	51,700	67,800
Goodwill and other intangible assets, net	134,400	141,000
Investments in and advances to consolidated affiliates, net	831,700	746,600
Other long-term assets	181,800	139,600
Total assets	1,470,000	1,427,900
Liabilities and equity
Total current liabilities	166,700	202,300
Long-term debt	10,100	11,300
Other long-term liabilities	13,100	8,800
Total liabilities	189,900	222,400
Total equity	1,280,100	1,205,500
Total liabilities and equity	1,470,000	1,427,900
Eliminations [Member]
Assets
Total current assets	(114,500)	(17,100)
Property and equipment, net	0	0
Goodwill and other intangible assets, net	0	0
Investments in and advances to consolidated affiliates, net	(3,171,600)	(3,009,300)
Other long-term assets	0	0
Total assets	(3,286,100)	(3,026,400)
Liabilities and equity
Total current liabilities	(114,500)	(17,100)
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	(114,500)	(17,100)
Total equity	(3,171,600)	(3,009,300)
Total liabilities and equity	$ (3,286,100)	$ (3,026,400)