Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 397,498	$ 257,621
Total Regulatory Liabilities	742,842	683,717
Cost of removal
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	464,980	447,356
Future tax benefits due to customers
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	118,051	118,051
Pension and retiree group health
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	102,120	88,728
Other components of net periodic benefit cost
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	15,160	10,348
PCBA
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	12,642	8,972
Incremental cost balancing account (ICBA)
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	12,704	0
IRMA long-term regulatory liability
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	8,032	0
Health Cost Balancing Account (HCBA)
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	3,606	3,242
Net WRAM and MCBA long-term payable
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	2,860	2,071
Conservation Expense Balancing Account
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,058	1,200
RSF regulatory liability
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	0	2,116
Other regulatory liabilities
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Liabilities	1,629	1,633
Future tax benefits due to customers
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	158,486	158,486
IRMA long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 92,065	3,430
MWRAM
Regulatory Assets and Liabilities [Line Items]
Recovery Period	1 year
Total Regulatory Assets	$ 38,566	0
Other accrued benefits
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	26,917	25,363
Asset retirement obligations, net
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	28,311	26,686
Tank coating
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 20,480	19,602
Customer assistance program (CAP) and Rate support fund (RSF) accounts receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	1 year
Total Regulatory Assets	$ 10,015	2,459
Net WRAM and Modified Cost Balancing Account (MCBA) long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	5,199	10,738
PCBA
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	4,829	4,182
Recoverable property losses
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	2,791	3,121
Other regulatory assets
Regulatory Assets and Liabilities [Line Items]
Total Regulatory Assets	$ 9,839	$ 3,554
Minimum | IRMA long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	1 year
Maximum | IRMA long-term accounts receivable
Regulatory Assets and Liabilities [Line Items]
Recovery Period	2 years