Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		$ 1,890,180	$ 1,232,404	$ 3,048,364	$ 2,206,630
Costs of revenue, excluding depreciation and amortization		1,626,335	1,068,182	2,597,469	1,952,583
Depreciation and amortization		45,379	40,657	88,282	79,664
General and administrative expenses		70,823	67,852	135,604	127,900
Interest expense (income), net		14,791	12,639	27,388	24,797
Equity in (earnings) losses of unconsolidated affiliates		(6,060)	(489)	(7,706)	(3,555)
Other expense (income), net		146	1,524	576	(11,830)
Income before income taxes		138,766	42,039	206,751	37,071
Provision for income taxes		(55,434)	(17,601)	(82,792)	(15,514)
Net income (loss) before equity in income from subsidiaries		83,300	24,400	124,000	21,600
Equity in income (losses) from subsidiaries, net of tax		0	0	0	0
Net income		83,332	24,438	123,959	21,557
Net income attributable to non-controlling interests		1,664	350	1,321	162
Net income attributable to MasTec, Inc.	[1]	81,668	24,088	122,638	21,395
Comprehensive income (loss)		81,197	20,108	123,638	14,841
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		600	600	1,200	1,200
Interest expense (income), net		0	0	0	0
Equity in (earnings) losses of unconsolidated affiliates		0	0	0	0
Other expense (income), net		0	0	0	0
Income before income taxes		(600)	(600)	(1,200)	(1,200)
Provision for income taxes		200	200	400	500
Net income (loss) before equity in income from subsidiaries		(400)	(400)	(800)	(700)
Equity in income (losses) from subsidiaries, net of tax		82,100	24,400	123,400	22,100
Net income		81,700	24,000	122,600	21,400
Net income attributable to non-controlling interests		0	0	0	0
Net income attributable to MasTec, Inc.		81,700	24,000	122,600	21,400
Comprehensive income (loss)		79,500	19,800	122,300	14,700
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		1,818,100	1,149,400	2,903,200	2,027,700
Costs of revenue, excluding depreciation and amortization		1,566,300	995,000	2,457,400	1,772,300
Depreciation and amortization		37,100	31,700	71,100	63,000
General and administrative expenses		66,500	61,500	126,000	111,500
Interest expense (income), net		30,400	27,800	58,300	55,200
Equity in (earnings) losses of unconsolidated affiliates		0	0	0	0
Other expense (income), net		(5,300)	1,800	(5,300)	(9,400)
Income before income taxes		123,100	31,600	195,700	35,100
Provision for income taxes		(44,700)	(12,600)	(71,300)	(14,000)
Net income (loss) before equity in income from subsidiaries		78,400	19,000	124,400	21,100
Equity in income (losses) from subsidiaries, net of tax		0	0	0	0
Net income		78,400	19,000	124,400	21,100
Net income attributable to non-controlling interests		0	0	0	0
Net income attributable to MasTec, Inc.		78,400	19,000	124,400	21,100
Comprehensive income (loss)		78,400	19,000	124,400	21,100
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		122,900	93,500	217,000	189,500
Costs of revenue, excluding depreciation and amortization		110,800	83,700	211,900	190,900
Depreciation and amortization		8,300	9,000	17,200	16,700
General and administrative expenses		3,700	5,800	8,400	15,200
Interest expense (income), net		(15,600)	(15,200)	(30,900)	(30,400)
Equity in (earnings) losses of unconsolidated affiliates		(6,100)	(500)	(7,700)	(3,600)
Other expense (income), net		5,400	(300)	5,900	(2,400)
Income before income taxes		16,300	11,000	12,300	3,100
Provision for income taxes		(10,900)	(5,200)	(11,900)	(2,000)
Net income (loss) before equity in income from subsidiaries		5,400	5,800	400	1,100
Equity in income (losses) from subsidiaries, net of tax		0	0	0	0
Net income		5,400	5,800	400	1,100
Net income attributable to non-controlling interests		1,700	400	1,300	200
Net income attributable to MasTec, Inc.		3,700	5,400	(1,000)	900
Comprehensive income (loss)		3,200	1,400	0	(5,600)
Eliminations [Member]
Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]
Revenue		(50,800)	(10,500)	(71,800)	(10,600)
Costs of revenue, excluding depreciation and amortization		(50,800)	(10,500)	(71,800)	(10,600)
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) losses of unconsolidated affiliates		0	0	0	0
Other expense (income), net		0	0	0	0
Income before income taxes		0	0	0	0
Provision for 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		(82,100)	(24,400)	(123,400)	(22,100)
Net income		(82,100)	(24,400)	(123,400)	(22,100)
Net income attributable to non-controlling interests		0	0	0	0
Net income attributable to MasTec, Inc.		(82,100)	(24,400)	(123,400)	(22,100)
Comprehensive income (loss)		$ (79,900)	$ (20,100)	$ (123,100)	$ (15,400)

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