Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 197,334	$ 182,701
Regulatory balancing account revenue	17,239	21,272
Total operating revenue	214,573	203,973
Total non-regulated revenue	5,221	5,081
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	108,891	105,433
Business
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41,920	40,548
Multiple residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	20,600	19,203
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,951	6,405
Public authorities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,429	9,245
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,543	1,867
Contract operating and maintenance revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,385	3,267
Other non-regulated revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,250	1,248
Non-regulated revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,635	4,515
Lease revenue	586	566
Total non-regulated revenue	$ 5,221	$ 5,081