Statement of Cash Flows, Supplemental Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Taxes and Interest Paid:
Income taxes paid	$ 27,370	$ 29,153	$ 13,684
Interest Paid, Excluding Capitalized Interest, Operating Activities	26,005	22,540	19,941
Non-Cash Transactions:
Accrued payables for investment in utility plant	40,034	32,855	27,861
Property installed by developers and conveyed	1,549	7,222	3,102
Noncash or Part Noncash Acquisition, Value of Assets Acquired	0	0	0
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	0	0	0
GSWC
Taxes and Interest Paid:
Income taxes paid	20,155	21,428	8,184
Interest Paid, Excluding Capitalized Interest, Operating Activities	22,294	21,156	19,681
Non-Cash Transactions:
Accrued payables for investment in utility plant	38,302	30,656	25,633
Property installed by developers and conveyed	1,549	7,222	3,102
Noncash or Part Noncash Acquisition, Value of Assets Acquired	0	0	71,324
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	$ 0	$ 0	$ 71,344