CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Income Statement [Abstract]
Operating revenue	$ 203,973	$ 270,749
Operations:
Water production costs	62,991	64,185
Administrative and general	34,174	35,596
Other operations	28,836	26,925
Maintenance	7,668	8,010
Depreciation and amortization	35,956	32,844
Income taxes	1,035	15,538
Property and other taxes	10,968	9,757
Total operating expenses	181,628	192,855
Net operating income	22,345	77,894
Other income and expenses:
Non-regulated revenue	5,081	5,098
Non-regulated expenses	(3,466)	(1,954)
Other components of net periodic benefit credit	4,800	3,273
Allowance for equity funds used during construction	1,797	1,742
Income taxes on other income and expenses	(1,703)	(1,321)
Net other income	6,509	6,838
Interest expense:
Interest expense	16,509	15,800
Allowance for borrowed funds used during construction	(857)	(758)
Net interest expense	15,652	15,042
Net income	13,202	69,690
Net loss attributable to noncontrolling interest	(129)	(227)
Net income attributable to California Water Service Group	$ 13,331	$ 69,917
Earnings per share:
Basic (in dollars per share)	$ 0.22	$ 1.21
Diluted (in dollars per share)	$ 0.22	$ 1.21
Weighted average shares outstanding:
Basic (in shares)	59,511	57,733
Diluted (in shares)	59,566	57,774