CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 61,116	$ 60,554	$ 116,368	$ 170,621
Other comprehensive income (loss):
Unrecoverable pension benefit plan costs, net of tax of $0, $3,823, $0, and $3,823, respectively	0	3,823	0	(9,840)
Amortization of defined benefit pension plans, net of tax of $60, $250, $180, and $250, respectively	154	48	462	643
Other comprehensive income (loss), net of tax	154	3,871	462	(9,197)
Comprehensive income	61,270	64,425	116,830	161,424
Comprehensive loss attributable to noncontrolling interest	(114)	(126)	(361)	(527)
Comprehensive income attributable to California Water Service Group	$ 61,384	$ 64,551	$ 117,191	$ 161,951