Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		$ 1,955,752	$ 1,586,181	$ 5,004,116	$ 3,792,811
Costs of revenue, excluding depreciation and amortization		1,726,173	1,368,988	4,323,642	3,321,571
Depreciation and amortization		50,101	42,584	138,384	122,249
General and administrative expenses		66,397	67,131	202,001	195,031
Interest expense (income), net		17,578	13,097	44,966	37,895
Equity in earnings of unconsolidated affiliates		(7,399)	6	(15,105)	(3,549)
Other (income) expense, net		(4,677)	(971)	(4,102)	(12,803)
Income before income taxes		107,579	95,346	314,330	132,417
(Provision for) benefit from income taxes		(43,378)	(38,816)	(126,170)	(54,331)
Net income (loss) before equity in income from subsidiaries		64,200	56,500	188,200	78,100
Equity in income (losses) from subsidiaries, net of tax		0	0	0	0
Net income		64,201	56,530	188,160	78,086
Net income attributable to non-controlling interests		449	253	1,770	414
Net income attributable to MasTec, Inc.	[1]	63,752	56,277	186,390	77,672
Comprehensive income (loss)		65,650	54,731	189,288	69,571
Reportable Legal Entities [Member] | MasTec, Inc. [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		0	0	0	0
Costs of revenue, excluding depreciation and amortization		0	0	0	0
Depreciation and amortization		0	0	0	0
General and administrative expenses		500	600	1,700	1,700
Interest expense (income), net		0	0	0	0
Equity in earnings of unconsolidated affiliates		0	0	0	0
Other (income) expense, net		0	0	0	0
Income before income taxes		(500)	(600)	(1,700)	(1,700)
(Provision for) benefit from income taxes		200	200	600	600
Net income (loss) before equity in income from subsidiaries		(300)	(400)	(1,100)	(1,100)
Equity in income (losses) from subsidiaries, net of tax		64,100	56,700	187,500	78,800
Net income		63,800	56,300	186,400	77,700
Net income attributable to non-controlling interests		0	0	0	0
Net income attributable to MasTec, Inc.		63,800	56,300	186,400	77,700
Comprehensive income (loss)		65,200	54,500	187,500	69,200
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		1,860,300	1,493,900	4,763,400	3,521,500
Costs of revenue, excluding depreciation and amortization		1,640,300	1,282,300	4,097,700	3,054,500
Depreciation and amortization		41,100	33,700	112,200	96,600
General and administrative expenses		61,700	60,600	187,700	172,100
Interest expense (income), net		33,200	28,600	91,500	83,800
Equity in earnings of unconsolidated affiliates		0	0	0	0
Other (income) expense, net		(4,600)	(3,400)	(9,900)	(12,700)
Income before income taxes		88,600	92,100	284,200	127,200
(Provision for) benefit from income taxes		(33,800)	(33,400)	(104,900)	(47,300)
Net income (loss) before equity in income from subsidiaries		54,800	58,700	179,300	79,900
Equity in income (losses) from subsidiaries, net of tax		0	0	0	0
Net income		54,800	58,700	179,300	79,900
Net income attributable to non-controlling interests		0	0	0	0
Net income attributable to MasTec, Inc.		54,800	58,700	179,300	79,900
Comprehensive income (loss)		54,900	58,700	179,300	79,900
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		130,300	112,700	347,400	302,200
Costs of revenue, excluding depreciation and amortization		120,700	107,200	332,600	298,000
Depreciation and amortization		9,000	8,900	26,200	25,600
General and administrative expenses		4,200	5,900	12,600	21,200
Interest expense (income), net		(15,600)	(15,500)	(46,500)	(45,900)
Equity in earnings of unconsolidated affiliates		(7,400)	0	(15,100)	(3,500)
Other (income) expense, net		(100)	2,300	5,800	(100)
Income before income taxes		19,500	3,900	31,800	6,900
(Provision for) benefit from income taxes		(9,900)	(5,600)	(21,900)	(7,600)
Net income (loss) before equity in income from subsidiaries		9,600	(1,700)	9,900	(700)
Equity in income (losses) from subsidiaries, net of tax		0	0	0	0
Net income		9,600	(1,700)	9,900	(700)
Net income attributable to non-controlling interests		400	300	1,800	400
Net income attributable to MasTec, Inc.		9,200	(2,000)	8,100	(1,100)
Comprehensive income (loss)		11,100	(3,600)	11,100	(9,200)
Eliminations [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		(34,800)	(20,400)	(106,700)	(30,900)
Costs of revenue, excluding depreciation and amortization		(34,800)	(20,400)	(106,700)	(30,900)
Depreciation and amortization		0	0	0	0
General and administrative expenses		0	0	0	0
Interest expense (income), net		0	0	0	0
Equity in earnings of unconsolidated affiliates		0	0	0	0
Other (income) expense, net		0	0	0	0
Income before income taxes		0	0	0	0
(Provision for) benefit from income taxes		0	0	0	0
Net income (loss) before equity in income from subsidiaries		0	0	0	0
Equity in income (losses) from subsidiaries, net of tax		(64,100)	(56,700)	(187,500)	(78,800)
Net income		(64,100)	(56,700)	(187,500)	(78,800)
Net income attributable to non-controlling interests		0	0	0	0
Net income attributable to MasTec, Inc.		(64,100)	(56,700)	(187,500)	(78,800)
Comprehensive income (loss)		$ (65,500)	$ (54,900)	$ (188,600)	$ (70,300)

[1] Calculated as total net income less amounts attributable to non-controlling interests.