Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash provided by (used in) operating activities	$ 178,625	$ 127,141
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(115,995)	(4,102)
Capital expenditures	(83,330)	(89,050)
Proceeds from sale of property and equipment	13,585	6,824
Payments for other investments	(77,105)	(8,858)
Proceeds from other investments	13,416	1,125
Net cash used in investing activities	(249,429)	(94,061)
Cash flows from financing activities:
Proceeds from credit facilities	2,002,430	1,186,816
Repayments of credit facilities	(1,840,409)	(1,149,930)
Repayments of other borrowings and capital lease obligations	(60,800)	(50,000)
Payments of acquisition-related contingent consideration	(18,843)	(19,822)
Distributions to non-controlling interests	(1,280)	0
Proceeds from stock-based awards, net	853	3,938
Other financing activities, net	(6,301)	1,385
Net financing activities and advances (to) from consolidated affiliates	0	0
Net cash provided by (used in) financing activities	75,622	(27,629)
Effect of currency translation on cash	237	(1,008)
Net increase in cash and cash equivalents	5,055	4,443
Cash and cash equivalents - beginning of period	38,767	4,984
Cash and cash equivalents - end of period	43,822	9,427
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:
Cash paid for acquisitions, net of cash acquired	0	0
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 from 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 acquisition-related contingent consideration	0	0
Distributions to non-controlling interests	0
Proceeds from stock-based awards, net	900	3,400
Other financing activities, net	0	1,400
Net financing activities and advances (to) from consolidated affiliates	(900)	(4,800)
Net cash provided by (used in) financing activities	0	0
Effect of currency translation on cash	0	0
Net increase 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	222,000	87,200
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(116,000)	(4,100)
Capital expenditures	(70,000)	(84,000)
Proceeds from sale of property and equipment	12,500	3,100
Payments for other investments	(3,800)	(3,800)
Proceeds from other investments	1,200	0
Net cash used in investing activities	(176,100)	(88,800)
Cash flows from financing activities:
Proceeds from credit facilities	1,988,100	1,093,800
Repayments of credit facilities	(1,817,400)	(1,056,100)
Repayments of other borrowings and capital lease obligations	(52,600)	(37,600)
Payments of acquisition-related contingent consideration	(18,800)	(16,500)
Distributions to non-controlling interests	0
Proceeds from stock-based awards, net	0	0
Other financing activities, net	(6,300)	0
Net financing activities and advances (to) from consolidated affiliates	(131,900)	15,100
Net cash provided by (used in) financing activities	(38,900)	(1,300)
Effect of currency translation on cash	0	0
Net increase in cash and cash equivalents	7,000	(2,900)
Cash and cash equivalents - beginning of period	28,300	4,700
Cash and cash equivalents - end of period	35,300	1,800
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	(43,400)	39,900
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	0	0
Capital expenditures	(13,300)	(5,100)
Proceeds from sale of property and equipment	1,100	3,700
Payments for other investments	(73,300)	(5,000)
Proceeds from other investments	12,200	1,100
Net cash used in investing activities	(73,300)	(5,300)
Cash flows from financing activities:
Proceeds from credit facilities	14,300	93,000
Repayments of credit facilities	(23,000)	(93,800)
Repayments of other borrowings and capital lease obligations	(8,300)	(12,400)
Payments of acquisition-related contingent consideration	0	(3,300)
Distributions to non-controlling interests	(1,300)
Proceeds from stock-based awards, net	0	500
Other financing activities, net	0	0
Net financing activities and advances (to) from consolidated affiliates	132,800	(10,300)
Net cash provided by (used in) financing activities	114,500	(26,300)
Effect of currency translation on cash	200	(1,000)
Net increase in cash and cash equivalents	(2,000)	7,300
Cash and cash equivalents - beginning of period	10,500	300
Cash and cash equivalents - end of period	8,500	7,600
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:
Cash paid for acquisitions, net of cash acquired	0	0
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 from 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 acquisition-related contingent consideration	0	0
Distributions to non-controlling interests	0
Proceeds from stock-based awards, net	0	0
Other financing activities, net	0	0
Net financing activities and advances (to) from consolidated affiliates	0	0
Net cash provided by (used in) financing activities	0	0
Effect of currency translation on cash	0	0
Net increase 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