Earnings Per Share (Narrative) (Detail) (USD $)	6 Months Ended			12 Months Ended		3 Months Ended		6 Months Ended						3 Months Ended				6 Months Ended									3 Months Ended				6 Months Ended					3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012		Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013 Restricted Stock [Member]	Jun. 30, 2012 Restricted Stock [Member]	Jun. 30, 2013 Restricted Stock [Member]	Jun. 30, 2012 Restricted Stock [Member]	Jun. 30, 2013 Convertible Debt [Member] Original 4.0% Notes [Member]		Jun. 30, 2012 Convertible Debt [Member] Original 4.0% Notes [Member]		Jun. 30, 2013 Convertible Debt [Member] New 4.0% Notes [Member]		Jun. 30, 2012 Convertible Debt [Member] New 4.0% Notes [Member]		Jun. 30, 2013 Convertible Debt [Member] New 4.0% Notes [Member]		Jun. 30, 2012 Convertible Debt [Member] New 4.0% Notes [Member]		Dec. 31, 2012 Convertible Debt [Member] New 4.0% Notes [Member]	Jun. 30, 2013 Convertible Debt [Member] Original 4.25% Notes [Member]		Jun. 30, 2012 Convertible Debt [Member] Original 4.25% Notes [Member]		Jun. 30, 2013 Convertible Debt [Member] New 4.25% Notes [Member]		Jun. 30, 2012 Convertible Debt [Member] New 4.25% Notes [Member]		Jun. 30, 2013 Convertible Debt [Member] New 4.25% Notes [Member]		Jun. 30, 2012 Convertible Debt [Member] New 4.25% Notes [Member]		Dec. 31, 2012 Convertible Debt [Member] New 4.25% Notes [Member]	Jun. 30, 2013 Convertible Debt [Member] Total New Senior Convertible Notes [Member]	Jun. 30, 2012 Convertible Debt [Member] Total New Senior Convertible Notes [Member]	Jun. 30, 2013 Convertible Debt [Member] Total New Senior Convertible Notes [Member]	Jun. 30, 2012 Convertible Debt [Member] Total New Senior Convertible Notes [Member]	Jun. 30, 2013 Convertible Debt [Member] Total Convertible Debt [Member]
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Basic earnings per share is computed by dividing earnings available to MasTec’s common shareholders by the weighted average number of common shares outstanding for the period. Diluted earnings per share is computed by dividing earnings by the number of fully diluted shares, which includes the effect of dilutive potential issuances of common shares as determined using earnings from continuing operations. The potential issuance of common shares upon the exercise, conversion or vesting, as applicable, of outstanding stock options and unvested restricted share awards, as calculated under the treasury stock method, as well as shares associated with the Company’s outstanding convertible debt securities, may be dilutive.
Anti-dilutive common stock equivalents, shares						123,077	136,158	61,878	1,066
Stock repurchase program, amount authorized					$ 150,000,000
Treasury stock acquired, shares		2,906,000	[1]	4,900,000	4,600,000
Treasury stock acquired, value				75,000,000	75,000,000
Principal amount										$ 9,600,000	[2]	$ 9,700,000	[2]	$ 105,322,000	[3]	$ 105,322,000	[3]	$ 105,322,000	[3]	$ 105,322,000	[3]	$ 105,300,000	$ 3,000,000	[2]	$ 3,000,000	[2]	$ 97,000,000	[3]	$ 97,000,000	[3]	$ 97,000,000	[3]	$ 97,000,000	[3]	$ 97,000,000					$ 215,000,000
Debt instrument, interest rate										4.00%				4.00%				4.00%					4.25%				4.25%				4.25%
Debt instrument, convertible, number of conversion shares, principal amount														6,683,000		6,683,000		6,683,000		6,683,000							6,268,000		6,268,000		6,268,000		6,268,000			13,000,000	13,000,000	13,000,000	13,000,000

[1] (1) See Note 2 - Earnings Per Share for share repurchase plan details.

[2] Dilutive shares associated with the Original Convertible Notes are attributable to the underlying principal amounts.

[3] Dilutive shares associated with the New Convertible Notes are attributable to the weighted average premium value, in shares, of the conversion shares underlying the New Convertible Notes in excess of the respective principal amounts thereof.