Quarterly Information (Unaudited) (Schedule of Quarterly Financial Information (Unaudited)) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2014	[1]	Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Jun. 30, 2014		Sep. 30, 2014		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]
Revenue	$ 1,231,300		$ 1,315,488		$ 1,107,232		$ 957,818		$ 1,159,100		$ 1,269,400		$ 977,600		$ 918,600		$ 2,065,050		$ 3,380,538		$ 4,611,803	$ 4,324,787	$ 3,726,789
Costs of revenue, excluding depreciation and amortization	1,063,100		1,122,861		950,715		841,324		987,000		1,081,100		822,700		791,500		1,792,040		2,914,901		3,977,963	3,682,367	3,239,195
Net income from continuing operations	26,600		49,445		33,738		12,264		42,900		49,900		35,500		19,300		46,002		95,447		122,001	147,672	116,639
Net loss from discontinued operations	(5,900)		(320)		(149)		(122)		(1,300)		(3,700)		(500)		(900)		(272)		(592)		(6,452)	(6,456)	(9,223)
Net (loss) income attributable to non-controlling interests	(400)		139		(136)		45		100		100		100		0		(91)		48		(374)	266	(10)
Net income attributable to MasTec, Inc.	$ 21,100		$ 48,986		$ 33,725		$ 12,097		$ 41,500		$ 46,100		$ 34,900		$ 18,400		$ 45,821		$ 94,807		$ 115,923	$ 140,950	$ 107,426
Basic earnings (loss) per share:
Continuing operations (in dollars per share)	$ 0.33		$ 0.60		$ 0.43		$ 0.16		$ 0.55		$ 0.65		$ 0.46		$ 0.25		$ 0.59		$ 1.21		$ 1.53	$ 1.92	$ 1.49
Discontinued operations (in dollars per share)	(0.07)		0.00		0.00		0.00		(0.02)		(0.05)		(0.01)		(0.01)		0.00		(0.01)		(0.08)	(0.09)	(0.12)
Total basic earnings per share (in dollars per share)	0.26	[2]	0.60	[2],[3]	0.43	[2],[3]	0.16	[2],[3]	0.54	[2]	0.60	[2]	0.46	[2]	0.24	[2]	0.59	[3]	1.20	[3]	1.45	1.83	1.37
Diluted earnings (loss) per share:
Continuing operations (in dollars per share)	0.32		0.57		0.39		0.14		0.50		0.59		0.42		0.23		0.53		1.11		1.42	1.74	1.42
Discontinued operations (in dollars per share)	(0.07)		0.00		0.00		0.00		(0.02)		(0.04)		(0.01)		(0.01)		0.00		(0.01)		(0.07)	(0.08)	(0.11)
Total diluted earnings per share (in dollars per share)	$ 0.25	[2]	$ 0.57	[2],[3]	$ 0.39	[2],[3]	$ 0.14	[2],[3]	$ 0.49	[2]	$ 0.54	[2]	$ 0.41	[2]	$ 0.22	[2]	$ 0.53	[3]	$ 1.10	[3]	$ 1.35	$ 1.66	$ 1.31

[1] Preliminary, unaudited fourth quarter and full year 2014 results were previously issued pursuant to a press release dated February 26, 2015 and not previously filed in a report under the Securities Exchange Act of 1934, as amended. The unaudited quarterly information for the three month period ended December 31, 2014 in the table above includes the effect of adjustments determined by management following the review process described in Note 2 - Independent Investigation of the Audit Committee and Related Restatements.

[2] Earnings per share calculations, including the sum of the individual quarterly earnings per share amounts to the full year earnings per share amounts, may contain slight summation differences due to rounding.

[3] Earnings per share calculations may contain slight summation differences due to rounding.