Earnings Per Share (Narrative) (Details) - shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Basic earnings or loss per share is computed by dividing net income or loss attributable to MasTec by the weighted average number of common shares outstanding for the period, which excludes non-participating unvested restricted share awards. Diluted earnings per share is computed by dividing net income or loss attributable to MasTec by the weighted average number of fully diluted shares, as calculated under the treasury stock method, which includes the potential effect of dilutive common stock equivalents, such as outstanding but unexcercised stock options and/or issued but unvested restricted shares. If the Company reports a loss, rather than income, the computation of diluted loss per share excludes dilutive common stock equivalents, as their effect would be anti-dilutive. For the nine month period ended September 30, 2015, the Company reported a net loss, which resulted in the exclusion of 648,379 weighted average dilutive common stock equivalents from the calculation of diluted loss per share.
Common Stock Equivalents Excluded Due To Net Loss [Member] | Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average anti-dilutive common stock equivalents (in shares)		648,379