Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 194,206	$ 198,660	$ 339,431	$ 357,592
Regulatory balancing account revenue	(162)	7,534	(14,287)	21,595
Operating revenue	194,044	206,194	325,144	379,187
Total non-regulated revenue	4,485	7,002	9,108	12,199
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	108,741	116,638	192,775	208,380
Business
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	37,846	39,278	69,820	71,441
Multiple residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,504	16,193	31,501	31,010
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,874	6,314	11,508	12,087
Public authorities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8,991	10,884	15,416	17,869
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,250	9,353	18,411	16,805
Operating and maintenance revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,075	3,233	6,310	6,638
Other non-regulated revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	800	3,081	1,582	4,231
Non-regulated revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,875	6,314	7,892	10,869
Lease revenue	610	688	1,216	1,330
Total non-regulated revenue	$ 4,485	$ 7,002	$ 9,108	$ 12,199