CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 190,085	$ 51,376	$ 95,263
Other comprehensive income (loss):
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Tax	(9,840)	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	1,175	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	1,448	0	0
Other comprehensive loss, net of tax	(7,217)	0	0
Comprehensive income	182,868	51,376	95,263
Comprehensive loss attributable to noncontrolling interest	(722)	(535)	(748)
Comprehensive income attributable to California Water Service Group	$ 183,590	$ 51,911	$ 96,011