3. Revenue

Disaggregation of Revenue

The following tables disaggregate revenue by end market, customer type and contract type, which the Company believes best depicts how the nature, amount, timing and uncertainty of its revenue and cash flows are affected by economic factors for the year ended December 31, 2018.



	Year Ended December 31,
(in thousands)	2018
Civil segment revenue by end market:
Mass transit	$	702,614
Bridges		431,202
Highways		202,423
Tunneling		103,980
Other		145,874
Total Civil segment revenue	$	1,586,093



	Year Ended December 31,
(in thousands)	2018
Building segment revenue by end market:
Health care facilities	$	428,819
Commercial and industrial facilities		374,312
Hospitality and gaming		301,871
Municipal and government		261,496
Mixed use		150,549
Education facilities		145,147
Mass transit		67,588
Other		131,917
Total Building segment revenue	$	1,861,699



	Year Ended December 31,
(in thousands)	2018
Specialty Contractors segment revenue by end market:
Mass transit	$	296,092
Commercial and industrial facilities		189,632
Mixed use		163,308
Education facilities		99,214
Transportation		83,551
Multi-unit residential		81,023
Health care facilities		52,392
Other		41,658
Total Specialty Contractors segment revenue	$	1,006,870



	Year Ended December 31, 2018
					Specialty
(in thousands)	Civil		Building		Contractors		Total
Revenue by customer type:
State and local agencies	$	1,294,630	$	617,133	$	406,782	$	2,318,545
Federal agencies		95,567		201,745		53,335		350,647
Private owners		195,896		1,042,821		546,753		1,785,470
Total revenue	$	1,586,093	$	1,861,699	$	1,006,870	$	4,454,662

State and local agencies. The Company’s state and local government customers include state transportation departments, metropolitan authorities, cities, municipal agencies, school districts and public universities. Services provided to state and local customers are primarily pursuant to contracts awarded through competitive bidding processes. Construction services for state and local government customers have included mass-transit systems, bridges, highways, judicial and correctional facilities, schools and dormitories, health care facilities, convention centers, parking structures and other municipal buildings. The vast majority of the Company’s civil contracting and building construction services are provided in locations throughout the United States and its territories.

Federal agencies. The Company’s federal government customers include the U.S. State Department, the U.S. Navy, the U.S. Army Corps of Engineers, the U.S. Air Force and the National Park Service. Services provided to federal agencies are typically pursuant to competitively bid contracts for specific or multi-year assignments that involve new construction or infrastructure repairs or improvements. A portion of revenue from federal agencies is derived from projects in overseas locations.

Private owners. The Company’s private customers include real estate developers, health care companies, technology companies, hospitality and gaming resort owners, Native American sovereign nations, public corporations and private universities. Services are provided to private customers through negotiated contract arrangements, as well as through competitive bids.

Most federal, state and local government contracts contain provisions that permit the termination of contracts, in whole or in part, for the convenience of government customers, among other reasons.



	Year Ended December 31, 2018
					Specialty
(in thousands)	Civil		Building		Contractors		Total
Revenue by contract type:
Fixed price	$	1,054,473	$	377,538	$	857,742	$	2,289,753
Guaranteed maximum price		15,709		1,040,093		62,132		1,117,934
Unit price		469,305		32,468		32,562		534,335
Cost plus fee and other		46,606		411,600		54,434		512,640
Total revenue	$	1,586,093	$	1,861,699	$	1,006,870	$	4,454,662

Fixed price. Fixed price or lump sum contracts are most commonly used for projects in the Civil and Specialty Contractors segments and generally commit the Company to provide all of the resources required to complete a project for a fixed sum. Usually, fixed price contracts transfer more risk to the Company, but offer the opportunity for greater profits. Billings on fixed price contracts are typically based on estimated progress against predetermined contractual milestones.

Guaranteed maximum price (“GMP”). GMP contracts provide for a cost plus fee arrangement up to a maximum agreed upon price. These contracts place risks on the Company for amounts in excess of the GMP, but may permit an opportunity for greater profits than under cost plus fee contracts through sharing agreements with the owner on any cost savings that may be realized. Services provided by our Building segment to various private customers are often performed under GMP contracts. Billings on GMP contracts typically occur on a monthly basis and are based on actual costs incurred plus a negotiated margin.

Unit price. Unit price contracts are most prevalent for projects in the Civil and Specialty Contractors segments and generally commit the Company to provide an estimated or undetermined number of units or components that comprise a project at a fixed price per unit. This approach shifts the risk of estimating the quantity of units required to the project owner, but the risk of increased cost per unit is borne by the Company, unless otherwise allowed for in the contract. Billings on unit price contracts typically occur on a monthly basis and are based on actual quantity of work performed or completed during the billing period.

Cost plus fee. Cost plus fee contracts are used for many projects in the Building and Specialty Contractors segments. Cost plus fee contracts include cost plus fixed fee contracts and cost plus award fee contracts. Cost plus fixed fee contracts provide for reimbursement of approved project costs plus a fixed fee. Cost plus award fee contracts provide for reimbursement of the project costs plus a base fee, as well as an incentive fee based on cost and/or schedule performance. Cost plus fee contracts serve to minimize the Company’s financial risk, but may also limit profits. Billings on cost plus fee contracts typically occur on a monthly basis based on actual costs incurred plus a negotiated margin.

Changes in Contract Estimates that Impact Revenue

Changes to the total estimated contract revenue or cost, either due to unexpected events or revisions to management’s initial estimates, for a given project are recognized in the period in which they are determined. Net revenue recognized during the year ended December 31, 2018 related to performance obligations satisfied (or partially satisfied) in prior periods was $19.4 million for various projects, none of which was individually material.

Remaining Performance Obligations

Remaining performance obligations represent the transaction price of firm orders for which work has not been performed and exclude unexercised contract options. As of December 31, 2018, the aggregate amounts of the transaction prices allocated to the remaining performance obligations of the Company’s construction contracts are $4.6 billion, $2.3 billion and $1.7 billion for the Civil, Building and Specialty Contractors segments, respectively. The Company typically recognizes revenue on Civil segment projects over a period of three to five years, whereas for projects in the Building and Specialty Contractors segments, the Company typically recognizes revenue over a period of one to three years.