Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash (used in) provided by operating activities	$ 260,602	$ 81,019
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	(148)	(162,901)
Capital expenditures	(70,766)	(90,962)
Proceeds from sale of property and equipment	9,763	12,204
Payments for investments, net	(109,299)	(1,046)
Net cash used in investing activities	(170,450)	(242,705)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	1,329,610	1,319,623
Repayments of credit facilities	(1,240,122)	(955,151)
Repayments of senior convertible notes	0	(105,325)
Repayments of other borrowings and capital lease obligations	(51,300)	(54,100)
Repurchase of common stock	(100,000)	0
Proceeds from stock-based awards, net of tax withholdings	1,743	318
Excess tax benefit from stock-based compensation	56	3,494
Payments of acquisition-related contingent consideration	(44,757)	(60,341)
Payments of financing costs	(2,435)	(1,455)
Net financing activities and advances from (to) consolidated affiliates	0	0
Net cash (used in) provided by financing activities	(107,160)	146,978
Effect of currency translation on cash	103	(1,152)
Net decrease in cash and cash equivalents	(16,905)	(15,860)
Cash and cash equivalents - beginning of period	24,059	22,927
Cash and cash equivalents - end of period	7,154	7,067
Reportable Legal Entities [Member] | MasTec, Inc. [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash (used in) provided by operating activities	(1,100)	(900)
Cash flows (used in) provided by 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 investments, net	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 senior convertible notes		0
Repayments of other borrowings and capital lease obligations	0	0
Repurchase of common stock	(100,000)
Proceeds from stock-based awards, net of tax withholdings	2,100	2,900
Excess tax benefit from stock-based compensation	0	0
Payments of acquisition-related contingent consideration	0	0
Payments of financing costs	0	0
Net financing activities and advances from (to) consolidated affiliates	99,000	(2,000)
Net cash (used in) provided by financing activities	1,100	900
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 (used in) provided by operating activities	317,000	41,100
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	(100)	(40,000)
Capital expenditures	(58,200)	(75,600)
Proceeds from sale of property and equipment	8,400	10,300
Payments for investments, net	(109,300)	(1,000)
Net cash used in investing activities	(159,200)	(106,300)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	827,100	1,122,400
Repayments of credit facilities	(747,800)	(723,200)
Repayments of senior convertible notes		(105,300)
Repayments of other borrowings and capital lease obligations	(36,400)	(45,400)
Repurchase of common stock	0
Proceeds from stock-based awards, net of tax withholdings	(400)	(2,600)
Excess tax benefit from stock-based compensation	100	3,500
Payments of acquisition-related contingent consideration	(37,300)	(60,300)
Payments of financing costs	(2,400)	(1,500)
Net financing activities and advances from (to) consolidated affiliates	(169,200)	(125,200)
Net cash (used in) provided by financing activities	(166,300)	62,400
Effect of currency translation on cash	0	0
Net decrease in cash and cash equivalents	(8,500)	(2,800)
Cash and cash equivalents - beginning of period	18,500	5,400
Cash and cash equivalents - end of period	10,000	2,600
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash (used in) provided by operating activities	(55,300)	40,800
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	0	(122,900)
Capital expenditures	(12,600)	(15,400)
Proceeds from sale of property and equipment	1,400	1,900
Payments for investments, net	0	0
Net cash used in investing activities	(11,200)	(136,400)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	502,500	197,200
Repayments of credit facilities	(492,300)	(232,000)
Repayments of senior convertible notes		0
Repayments of other borrowings and capital lease obligations	(14,900)	(8,700)
Repurchase of common stock	0
Proceeds from stock-based awards, net of tax withholdings	0	0
Excess tax benefit from stock-based compensation	0	0
Payments of acquisition-related contingent consideration	(7,500)	0
Payments of financing costs	0	0
Net financing activities and advances from (to) consolidated affiliates	70,200	127,200
Net cash (used in) provided by financing activities	58,000	83,700
Effect of currency translation on cash	100	(1,200)
Net decrease in cash and cash equivalents	(8,400)	(13,100)
Cash and cash equivalents - beginning of period	5,600	17,600
Cash and cash equivalents - end of period	(2,800)	4,500
Eliminations [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash (used in) provided by operating activities	0	0
Cash flows (used in) provided by 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 investments, net	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 senior convertible notes		0
Repayments of other borrowings and capital lease obligations	0	0
Repurchase of common stock	0
Proceeds from stock-based awards, net of tax withholdings	0	0
Excess tax benefit from stock-based compensation	0	0
Payments of acquisition-related contingent consideration	0	0
Payments of financing costs	0	0
Net financing activities and advances from (to) consolidated affiliates	0	0
Net cash (used in) provided by 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