Revenue - Summary of Revenue Disaggregated by Service Type, and Contract Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 259,066	$ 253,408	$ 763,859	$ 805,588	$ 1,343,565	$ 1,371,305
Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	494,813	454,300	828,306	767,162	1,812,122	1,634,226
Master services agreement | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	375,502	375,860	639,047	611,515	1,410,909	1,229,388
Bid contract | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	119,311	78,440	189,259	155,647	401,213	404,838
Unit price contracts | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	365,253	355,487	608,389	591,172	1,397,473	1,323,034
Fixed price contracts | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36,011	4,426	63,556	42,965	133,515	107,697
Time and materials contracts | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	93,549	94,387	156,361	133,025	281,134	203,495
Gas infrastructure services | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	330,157	323,817	547,866	521,709	1,265,131	1,205,197
Electric power infrastructure services | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	95,286	61,366	167,606	113,667	301,656	136,900
Other | Centuri
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 69,370	$ 69,117	$ 112,834	$ 131,786	$ 245,335	$ 292,129