Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 314,096	$ 306,237	$ 753,013	$ 687,803
Regulatory balancing account revenue	(2,861)	(6,674)	27,149	126,808
Total operating revenue	311,235	299,563	780,162	814,611
Total non-regulated revenue	5,349	4,133	15,341	14,744
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	186,699	184,951	434,061	399,695
Business
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	56,284	56,225	144,926	132,680
Multiple residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22,766	21,795	62,692	56,707
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11,098	9,645	24,032	23,404
Public authorities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	19,039	18,140	41,295	36,020
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18,210	15,481	46,007	39,297
Contract operating and maintenance revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,546	3,384	10,052	9,820
Other non-regulated revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,218	143	3,557	3,092
Non-regulated revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,764	3,527	13,609	12,912
Lease revenue	585	606	1,732	1,832
Total non-regulated revenue	$ 5,349	$ 4,133	$ 15,341	$ 14,744