Revenue - Schedule of Regulated Operations Revenues: Natural Gas Distribution Segment (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total Regulated operations revenues	$ 743,532	$ 521,932	$ 1,743,390	$ 1,369,690
Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	695,335	535,520	1,657,565	1,369,878
Alternative revenue program revenues (deferrals)	(23,499)	(16,373)	6,055	(468)
Other revenues	4,703	2,785	12,777	280
Total Regulated operations revenues	676,539	521,932	1,676,397	1,369,690
Residential | Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	514,586	403,143	1,147,055	983,108
Small commercial | Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	123,984	81,398	312,800	220,476
Large commercial | Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	20,161	12,673	64,859	44,639
Industrial/other | Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,972	13,770	38,515	33,310
Transportation | Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 26,632	$ 24,536	$ 94,336	$ 88,345