Acquisitions (Narrative) (Details) (USD $)	3 Months Ended					0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Earn-out Arrangements [Member]	Mar. 31, 2013 Earn-out Arrangements [Member]	Mar. 31, 2014 2014 and 2013 Acquisitions [Member]	Jan. 02, 2014 2014 Acquisitions [Member]	Mar. 31, 2014 2014 Acquisitions [Member]	Jan. 02, 2014 2014 Acquisitions [Member] Earn-out Arrangements [Member]	Mar. 31, 2014 Big Country [Member]	May 02, 2013 Big Country [Member]	Mar. 31, 2014 Other 2013 Acquisitions [Member]
Business Acquisition [Line Items]
Business combination, provisional information, initial accounting incomplete, items					As of March 31, 2014, the allocations of purchase price to the fair values of tangible and intangible assets and liabilities, including the estimated values of contingent earn-out obligations and the estimated useful lives of acquired assets for these acquisitions are provisional and remain preliminary. Management continues to assess the valuation of these items and any ultimate purchase price adjustments that may result based on the final net assets and net working capital of the acquired businesses, as prescribed in the corresponding purchase agreements.
Business combination, provisional information, initial accounting incomplete, reasons	The Company will revise its preliminary allocations for acquired businesses if new information is obtained about the facts and circumstances existing as of the date of acquisition, or for purchase price adjustments based on the final net assets and net working capital of the acquired businesses, as prescribed in the applicable purchase agreement.
Business combination, description of acquired entity							Effective January 1, 2014, MasTec acquired a telecommunications services firm that specializes in the engineering, installation, furnishing and integration of telecommunications equipment for an aggregate purchase price composed of approximately $23.8 million in cash and a five year earn-out, valued at $8.7 million as of the date of acquisition. This company is included in MasTec's Communications segment.		Big Country is a North American oil and gas pipeline and facility construction services company, headquartered in Calgary, Alberta, Canada.		Effective April 1, 2013, MasTec acquired a former subcontractor to its wireless business, which provides self-perform communications tower construction, installation, maintenance and other services in support of telecommunications infrastructure construction in the Company's Communications segment. In addition, effective August 1, 2013, MasTec acquired an electrical transmission services company, which focuses primarily on substation construction activities and is included within the Company's Electrical Transmission segment.
Acquisition payments in cash						$ 23,800,000
Estimated fair value of contingent consideration			8,700,000	0				8,700,000
Earn-out period								5 years
Effective date of acquisition									May 01, 2013
Business combination, percentage of voting interests acquired										100.00%
Business combination, name of acquired entity									Big Country Energy Services, Inc. and its affiliated operating companies (collectively, "Big Country").
Business combination, acquisition costs	$ 200,000	$ 400,000