Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	$ 154,173	$ 15,851
Cash flows from investing activities:
Capital expenditures	(28,901)	(13,343)
Proceeds from sale of property and equipment	511	2,237
Payments for other investments	(53,347)	(1,514)
Proceeds from other investments	12,118	0
Net cash used in investing activities	(69,619)	(12,620)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	361,743	335,747
Repayments of credit facilities	(447,112)	(320,742)
Repayments of other borrowings and capital lease obligations	(14,300)	(20,600)
Payments of financing costs	(5,973)	0
Distributions to non-controlling interests	(1,280)	0
(Payments for) proceeds from stock-based awards, net	(761)	1,817
Other financing activities, net	0	248
Net financing activities and advances from (to) consolidated affiliates	0	0
Net cash used in financing activities	(107,794)	(3,648)
Effect of currency translation on cash	160	(682)
Net decrease in cash and cash equivalents	(23,080)	(1,099)
Cash and cash equivalents - beginning of period	38,767	4,984
Cash and cash equivalents - end of period	15,687	3,885
Reportable Legal Entities [Member] | MasTec, Inc. [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	0	0
Cash flows from investing activities:
Capital expenditures	0	0
Proceeds from sale of property and equipment	0	0
Payments for other investments	0	0
Proceeds from other investments	0	0
Net cash used in investing activities	0	0
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	0	0
Repayments of credit facilities	0	0
Repayments of other borrowings and capital lease obligations	0	0
Payments of financing costs	0
Distributions to non-controlling interests	0
(Payments for) proceeds from stock-based awards, net	(800)	2,000
Other financing activities, net		0
Net financing activities and advances from (to) consolidated affiliates	800	(2,000)
Net cash used in financing activities	0	0
Effect of currency translation on cash	0	0
Net decrease in cash and cash equivalents	0	0
Cash and cash equivalents - beginning of period	0	0
Cash and cash equivalents - end of period	0	0
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	166,500	(5,300)
Cash flows from investing activities:
Capital expenditures	(21,000)	(12,200)
Proceeds from sale of property and equipment	400	1,500
Payments for other investments	0	0
Proceeds from other investments	0	0
Net cash used in investing activities	(20,600)	(10,700)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	357,200	286,800
Repayments of credit facilities	(439,000)	(270,500)
Repayments of other borrowings and capital lease obligations	(11,700)	(16,300)
Payments of financing costs	(6,000)
Distributions to non-controlling interests	0
(Payments for) proceeds from stock-based awards, net	0	(200)
Other financing activities, net		200
Net financing activities and advances from (to) consolidated affiliates	(73,800)	13,600
Net cash used in financing activities	(173,300)	13,600
Effect of currency translation on cash	0	0
Net decrease in cash and cash equivalents	(27,400)	(2,400)
Cash and cash equivalents - beginning of period	28,300	4,800
Cash and cash equivalents - end of period	900	2,400
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	(12,300)	21,200
Cash flows from investing activities:
Capital expenditures	(7,900)	(1,100)
Proceeds from sale of property and equipment	100	700
Payments for other investments	(53,300)	(1,500)
Proceeds from other investments	12,100	0
Net cash used in investing activities	(49,000)	(1,900)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	4,500	48,900
Repayments of credit facilities	(8,100)	(50,200)
Repayments of other borrowings and capital lease obligations	(2,600)	(4,300)
Payments of financing costs	0
Distributions to non-controlling interests	(1,300)
(Payments for) proceeds from stock-based awards, net	0	0
Other financing activities, net		0
Net financing activities and advances from (to) consolidated affiliates	73,000	(11,600)
Net cash used in financing activities	65,500	(17,200)
Effect of currency translation on cash	200	(700)
Net decrease in cash and cash equivalents	4,300	1,400
Cash and cash equivalents - beginning of period	10,500	300
Cash and cash equivalents - end of period	14,800	1,700
Eliminations [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	0	0
Cash flows from investing activities:
Capital expenditures	0	0
Proceeds from sale of property and equipment	0	0
Payments for other investments	0	0
Proceeds from other investments	0	0
Net cash used in investing activities	0	0
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	0	0
Repayments of credit facilities	0	0
Repayments of other borrowings and capital lease obligations	0	0
Payments of financing costs	0
Distributions to non-controlling interests	0
(Payments for) proceeds from stock-based awards, net	0	0
Other financing activities, net		0
Net financing activities and advances from (to) consolidated affiliates	0	0
Net cash used in financing activities	0	0
Effect of currency translation on cash	0	0
Net decrease in cash and cash equivalents	0	0
Cash and cash equivalents - beginning of period	0	0
Cash and cash equivalents - end of period	$ 0	$ 0