Note 13—Reportable Segments

We segregate our business into five reportable segments: the Power segment, the Pipeline segment, the Utilities segment, the Transmission segment, which is a new reportable segment created in connection with the acquisition of Willbros, and the Civil segment. Each of our reportable segments is comprised of similar business units that specialize in services unique to the segment. Driving the end-user focused segments are differences in the economic characteristics of each segment, the nature of the services provided by each segment; the production processes of each segment; the type or class of customer using the segment’s services; the methods used by the segment to provide the services; and the regulatory environment of each segment’s customers.

The classification of revenue and gross profit for segment reporting purposes can at times require judgment on the part of management. Our segments may perform services across industries or perform joint services for customers in multiple industries. To determine reportable segment gross profit, certain allocations, including allocations of shared and indirect costs, such as facility costs, equipment costs and indirect operating expenses, were made.

The following is a brief description of the reportable segments:

The Power segment operates throughout the United States and in Canada and specializes in a range of services that include full EPC project delivery, turnkey construction, retrofits, upgrades, repairs, outages, and maintenance for entities in the petroleum, petrochemical, water, and other industries.

The Pipeline segment operates throughout the United States and specializes in a range of services, including pipeline construction, pipeline maintenance, pipeline facility work, compressor stations, pump stations, metering facilities, and other pipeline related services for entities in the petroleum and petrochemical industries.

The Utilities segment operates primarily in California, the Midwest, and the Southeast regions of the United States and specializes in a range of services, including utility line installation and maintenance, gas and electric distribution, streetlight construction, substation work, and fiber optic cable installation.

The Transmission segment operates primarily in the Southeastern and Gulf Coast regions of the United States and specializes in a range of services in electric and gas transmission and distribution, including comprehensive engineering, procurement, maintenance and construction, repair, and restoration of utility infrastructure.

The Civil segment operates primarily in the Southeastern and Gulf Coast regions of the United States and specializes in highway and bridge construction, airport runway and taxiway construction, demolition, heavy earthwork, soil stabilization, mass excavation, and drainage projects.

All intersegment revenue and gross profit, which was immaterial, has been eliminated in the following tables.

Segment Revenue

Revenue by segment for the years ended December 31, 2018, 2017 and 2016 was as follows (in thousands):


	2018			2017			2016
			% of			% of			% of
			Total			Total			Total
Segment	Revenue		Revenue	Revenue		Revenue	Revenue		Revenue
Power	$	694,048	23.6%	$	606,125	25.5%	$	478,653	24.0%
Pipeline		590,937	20.1%		465,570	19.5%		401,931	20.1%
Utilities		902,772	30.7%		806,523	33.9%		637,212	31.9%
Transmission (1)		286,749	9.8%		—	—		—	—
Civil		464,972	15.8%		501,777	21.1%		479,152	24.0%
Total	$	2,939,478	100.0%	$	2,379,995	100.0%	$	1,996,948	100.0%

(1)

Represents results from the June 1, 2018 acquisition date of Willbros to December 31, 2018.

Segment Gross Profit

Gross profit by segment for the years ended December 31, 2018, 2017 and 2016 was as follows (in thousands):


	2018			2017			2016
			% of			% of			% of
			Segment			Segment
Segment	Gross Profit		Revenue	Gross Profit		Revenue	Gross Profit		Revenue
Power	$	109,789	15.8%	$	65,675	10.8%	$	49,807	10.4%
Pipeline		66,602	11.3%		92,087	19.8%		68,100	16.9%
Utilities		111,825	12.4%		113,037	14.0%		100,071	15.7%
Transmission (1)		31,904	11.1%		—	—		—	—
Civil		5,617	1.2%		7,635	1.5%		(16,671)	(3.5%)
Total	$	325,737	11.1%	$	278,434	11.7%	$	201,307	10.1%

(1)

Represents results from the June 1, 2018 acquisition date of Willbros to December 31, 2018.

Geographic Region — Revenue and Total Assets

The majority of our revenue is derived from customers in the United States with approximately 2.9%, 0.3% and 0.6% generated from sources outside of the United States for the years ended December 31, 2018, 2017, and 2016, respectively. At December 31, 2018 and 2017, approximately 2.8% and 1.0%, respectively of total assets were located outside of the United States.