Debt (Narrative) (Detail) (USD $)	9 Months Ended										3 Months Ended	9 Months Ended		9 Months Ended	3 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Line of Credit [Member]	Sep. 30, 2012 Convertible Debt [Member]	Sep. 30, 2011 Convertible Debt [Member]	Sep. 30, 2012 Revolving Credit Facility [Member]	Sep. 30, 2012 Revolving Credit Facility [Member] Line of Credit [Member]	Dec. 31, 2011 Revolving Credit Facility [Member] Line of Credit [Member]	Sep. 30, 2012 Letter of Credit [Member]	Sep. 30, 2012 Letter of Credit [Member] Minimum [Member]	Sep. 30, 2012 Letter of Credit [Member] Maximum [Member]	Sep. 30, 2012 Total New Senior Convertible Notes [Member] Convertible Debt [Member]	Sep. 30, 2012 Total New Senior Convertible Notes [Member] Convertible Debt [Member]	Mar. 31, 2011 Total New Senior Convertible Notes [Member] Convertible Debt [Member]	Sep. 30, 2012 Total New Senior Convertible Notes [Member] Weighted Average [Member] Convertible Debt [Member]	Mar. 31, 2011 Original 4.0% Notes [Member] Convertible Debt [Member]	Mar. 31, 2011 Original 4.25% Notes [Member] Convertible Debt [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding						$ 10,000,000	$ 60,000,000
Letters of credit issued								99,400,000
Line of credit facility, remaining borrowing capacity	490,600,000
Line of credit facility, capacity available for issuance of letters of credit								250,600,000
Line of credit interest rate					2.48%				1.125%	2.25%
Unused credit facility fee		0.40%
Debt instrument, exchanged amount			0	202,322,000											105,300,000	97,000,000
Unamortized debt discount and financing costs													$ 17,400,000
Debt instrument, effective interest rate											6.73%	6.73%
Debt instrument, convertible, remaining discount amortization period														2 years
Debt instruments, guarantees	The Company’s 7.625% senior notes, New Notes and Original Notes are fully and unconditionally guaranteed on an unsecured, unsubordinated, joint and several basis by the Company's existing and future 100%-owned direct and indirect domestic subsidiaries that are guarantors of the Company's Credit Facility or other outstanding indebtedness.
Debt instruments, covenant compliance	MasTec was in compliance with all provisions and covenants pertaining to its outstanding debt instruments as of September 30, 2012 and December 31, 2011.