Revenue (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Summary of Revenue Disaggregated by Service Type and Contract Type

Gas operating revenues on the Consolidated Statements of Income of both the Company and Southwest include revenue from contracts with customers, which is shown below disaggregated by customer type, and various categories of revenue:

	December 31,
(Thousands of dollars)	2018		2017		2016
Residential	$	887,220	$	857,204	$	895,330
Small commercial	255,083		243,513		251,092
Large commercial	53,192		52,379		53,582
Industrial/other	23,489		22,026		19,753
Transportation	86,990		87,759		87,106
Revenue from contracts with customers	1,305,974		1,262,881		1,306,863
Alternative revenue program revenues (deferrals)	45,979		35,347		12,530
Other revenues (a)	5,775		4,080		2,019
Total Gas operating revenues	$	1,357,728	$	1,302,308	$	1,321,412

(a) Includes various other revenues, and during the first six months of 2018, included $12.5 million as a reserve against revenue associated with a tax reform savings adjustment. During the third quarter of 2018, amounts previously recognized were reclassified to the various categories of revenue from contracts with customers when incorporated in tariff rates.

The following tables display Centuri’s revenue from contracts with customers disaggregated by service type and contract type:

(Thousands of dollars)	December 31,
	2018		2017		2016
Service Types:
Gas infrastructure services	$	1,123,682	$	891,139	$	914,970
Electric power infrastructure services	32,629		18,114		27,915
Other	365,974		337,231		196,193
Total Utility infrastructure services revenues	$	1,522,285	$	1,246,484	$	1,139,078

(Thousands of dollars)	December 31,
	2018		2017		2016
Contract Types:
Master services agreement	$	1,102,412	$	885,513	$	852,472
Bid contract	419,873		360,971		286,606
Total Utility infrastructure services revenues	$	1,522,285	$	1,246,484	$	1,139,078
Unit priced contracts	$	1,258,419	$	968,856	$	886,919
Fixed priced contracts	117,298		127,497		95,494
Time and materials contracts	146,568		150,131		156,665
Total Utility infrastructure services revenues	$	1,522,285	$	1,246,484	$	1,139,078

Summary of Information about Receivables, Revenue Earned on Contracts in Progress in Excess of Billings, Which are Included Within Accounts Receivable, Net of Allowances, and Amounts Billed in Excess of Revenue Earned on Contracts

The following table provides information about contracts receivable and revenue earned on contracts in progress in excess of billings (contract assets), both of which are included within Accounts receivable, net of allowances, and amounts billed in excess of revenue earned on contracts (contract liabilities), which are included in Other current liabilities as of December 31, 2018 and December 31, 2017 on the Company’s Consolidated Balance Sheets:

(Thousands of dollars)	December 31, 2018		December 31, 2017
Contracts receivable, net	$	186,249	$	221,859
Revenue earned on contracts in progress in excess of billings	87,520		5,768
Amounts billed in excess of revenue earned on contracts	4,211		9,602

Schedule of Construction Services Contracts Receivable

services contracts receivable consists of the following:

(Thousands of dollars)	December 31, 2018			December 31, 2017
Billed on completed contracts and contracts in progress	$	184,100		$	219,298
Other receivables	2,588			2,622
Contracts receivable, gross	186,688			221,920
Allowance for doubtful accounts	(439		)	(61		)
Contracts receivable, net	$	186,249		$	221,859