Southwest Gas Corporation is engaged in the business of purchasing, distributing and transporting natural gas in Arizona, Nevada and California. The Company operates through two segments: natural gas operations and construction services, which includes the operations of the Company's subsidiary, Centuri Construction Group, Inc., (Centuri). Its natural gas operations segment includes acquiring and arranging delivery of natural gas to its system in sufficient quantities. It acquires natural gas from various sources and a mix of purchase provisions, which includes spot market and firm supplies. Centuri is a full-service underground piping contractor that primarily provides utility companies with trenching and installation, replacement and maintenance services for energy distribution systems, and industrial construction solutions. Centuri operates through NPL Construction Co., Link-Line Contractors Ltd., W.S. Nicholls Construction, Inc. and related companies, and Brigadier Pipelines Inc.