Business and Organization	12 Months Ended
Business and Organization	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Organization	BUSINESS AND ORGANIZATION: Quanta Services, Inc. (Quanta) is a leading provider of specialty contracting services, delivering comprehensive infrastructure solutions for the electric power, energy and communications industries in the United States, Canada, Australia, Latin America and select other international markets. Quanta reports its results under two reportable segments: (1) Electric Power Infrastructure Services and (2) Pipeline and Industrial Infrastructure Services. As of December 31, 2018, Quanta changed the name of its Oil and Gas Infrastructure Services segment to the Pipeline and Industrial Infrastructure Services segment. There was no change to the composition of the segment, and the name change was made to better reflect the work performed within the segment and the diversity of its service offerings. Electric Power Infrastructure Services Segment The Electric Power Infrastructure Services segment provides comprehensive network solutions to customers in the electric power industry. Services performed by the Electric Power Infrastructure Services segment generally include the design, installation, upgrade, repair and maintenance of electric power transmission and distribution infrastructure and substation facilities along with other engineering and technical services. This segment also provides emergency restoration services, including the repair of infrastructure damaged by inclement weather, the energized installation, maintenance and upgrade of electric power infrastructure utilizing unique bare hand and hot stick methods and Quanta’s proprietary robotic arm technologies, and the installation of “smart grid” technologies on electric power networks. In addition, this segment provides services that support the development of renewable energy generation, including solar, wind and certain types of natural gas generation facilities, and related switchyards and transmission infrastructure. This segment also provides comprehensive communications infrastructure services to wireline and wireless telecommunications companies, cable multi-system operators and other customers within the communications industry; services in connection with the construction of electric power generation facilities; and the design, installation, maintenance and repair of commercial and industrial wiring. This segment also includes Quanta’s postsecondary educational institution, which specializes in pre-apprenticeship training, apprenticeship training and specialized utility task training for electric workers, and has been recently expanded to include curriculum for the gas distribution and communications industries. Pipeline and Industrial Infrastructure Services Segment The Pipeline and Industrial Infrastructure Services segment provides comprehensive infrastructure solutions to customers involved in the development, transportation, storage and processing of natural gas, oil and other products. Services performed by the Pipeline and Industrial Infrastructure Services segment generally include the design, installation, repair and maintenance of pipeline transmission and distribution systems, gathering systems, production systems, storage systems and compressor and pump stations, as well as related trenching, directional boring and mechanized welding services. In addition, this segment’s services include pipeline protection, integrity testing, rehabilitation and replacement, and the fabrication of pipeline support systems and related structures and facilities for natural gas utilities and midstream companies. Quanta also provides high-pressure and critical-path turnaround services to the downstream and midstream energy markets and instrumentation and electrical services, piping, fabrication and storage tank services. To a lesser extent, this segment serves the offshore and inland water energy markets and designs, installs and maintains fueling systems and water and sewer infrastructure. Acquisitions During the year ended December 31, 2018, Quanta acquired an electrical infrastructure services business specializing in substation construction and relay services, a postsecondary educational institution that provides pre-apprenticeship training and programs for experienced linemen and two communications infrastructure services businesses, all of which are located in the United States. The results of the acquired businesses have generally been included in Quanta’s Electric Power Infrastructure Services segment and have been included in Quanta’s consolidated financial statements beginning on the respective acquisition dates. On July 20, 2017, Quanta acquired Stronghold, Ltd. and Stronghold Specialty, Ltd. (collectively Stronghold), a specialized services business located in the United States that provides high-pressure and critical-path solutions to the downstream and midstream energy markets. The results of the acquired business are generally included in Quanta’s Pipeline and Industrial Infrastructure Services segment and have been included in Quanta’s consolidated financial statements beginning on the acquisition date. During the year ended December 31, 2017, Quanta also acquired a communications infrastructure services contractor and an electrical and communications contractor, both of which are located in the United States. The results of these acquired businesses are generally included in Quanta’s Electric Power Infrastructure Services segment and have been included in Quanta’s consolidated financial statements beginning on the respective acquisition dates. During 2016, Quanta completed five acquisitions. The results have been included in Quanta’s consolidated financial statements beginning on the respective acquisition dates. See further discussion regarding these acquisitions in Note 4.