Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash (used in) provided by operating activities	$ 165,853	$ 55,319
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	(148)	(162,901)
Capital expenditures	(48,431)	(67,566)
Proceeds from sale of property and equipment	4,146	8,752
Payments for investments, net	(69,795)	573
Net cash used in investing activities	(114,228)	(221,142)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	844,494	815,840
Repayments of credit facilities	(741,302)	(463,713)
Repayments of senior convertible notes	0	(105,325)
Repayments of other borrowings and capital lease obligations	(35,100)	(30,200)
Repurchase of common stock	(100,000)	0
Proceeds from stock-based awards, net of tax withholdings	1,849	(578)
Excess tax benefit from stock-based compensation	53	3,386
Payments of acquisition-related contingent consideration	(39,257)	(58,902)
Payments of financing costs	(1,053)	(1,298)
Net financing activities and advances (to) from consolidated affiliates	0	0
Net cash (used in) provided by financing activities	(70,368)	159,167
Effect of currency translation on cash	(561)	(347)
Net decrease in cash and cash equivalents	(19,304)	(7,003)
Cash and cash equivalents - beginning of period	24,059	22,927
Cash and cash equivalents - end of period	4,755	15,924
Reportable Legal Entities [Member] | MasTec, Inc. [Member]
Condensed Unaudited Consolidating Statements of Cash Flows [Line Items]
Net cash (used in) provided by operating activities	(700)	(500)
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	2,000	2,000
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 (to) from consolidated affiliates	98,700	(1,500)
Net cash (used in) provided by financing activities	700	500
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	238,800	22,100
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	(100)	(40,000)
Capital expenditures	(39,700)	(59,200)
Proceeds from sale of property and equipment	3,800	8,000
Payments for investments, net	(69,800)	600
Net cash used in investing activities	(105,800)	(90,600)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	514,600	776,000
Repayments of credit facilities	(437,000)	(430,400)
Repayments of senior convertible notes		(105,300)
Repayments of other borrowings and capital lease obligations	(25,000)	(27,400)
Repurchase of common stock	0
Proceeds from stock-based awards, net of tax withholdings	(200)	(2,600)
Excess tax benefit from stock-based compensation	100	3,400
Payments of acquisition-related contingent consideration	(39,300)	(58,900)
Payments of financing costs	(1,100)	(1,300)
Net financing activities and advances (to) from consolidated affiliates	(161,200)	(79,200)
Net cash (used in) provided by financing activities	(149,100)	74,300
Effect of currency translation on cash	0	0
Net decrease in cash and cash equivalents	(16,100)	5,800
Cash and cash equivalents - beginning of period	18,500	5,400
Cash and cash equivalents - end of period	2,400	11,200
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	(72,200)	33,700
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	0	(122,900)
Capital expenditures	(8,700)	(8,400)
Proceeds from sale of property and equipment	300	800
Payments for investments, net	0	0
Net cash used in investing activities	(8,400)	(130,500)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities	329,900	39,800
Repayments of credit facilities	(304,300)	(33,300)
Repayments of senior convertible notes		0
Repayments of other borrowings and capital lease obligations	(10,100)	(2,800)
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 (to) from consolidated affiliates	62,500	80,700
Net cash (used in) provided by financing activities	78,000	84,400
Effect of currency translation on cash	(600)	(300)
Net decrease in cash and cash equivalents	(3,200)	(12,700)
Cash and cash equivalents - beginning of period	5,600	17,600
Cash and cash equivalents - end of period	2,400	4,900
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 (to) from 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