CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Operating revenue	$ 266,307	$ 256,723	$ 645,494	$ 617,583
Operations:
Water production costs	88,750	84,951	221,195	214,688
Administrative and general	33,328	30,712	99,425	92,837
Other operations	26,676	24,686	81,945	63,318
Maintenance	8,433	7,739	23,389	21,118
Depreciation and amortization	28,844	27,232	86,387	81,516
Income taxes	5,890	1,705	5,927	3,576
Property and other taxes	9,440	8,546	25,853	24,213
Total operating expenses	201,361	185,571	544,121	501,266
Net operating income	64,946	71,152	101,373	116,317
Other income and expenses:
Non-regulated revenue	4,573	5,813	16,772	16,759
Non-regulated expenses	(6,905)	(5,779)	(22,432)	(12,354)
Other components of net periodic benefit credit	3,737	1,853	11,516	7,520
Allowance for equity funds used during construction	1,004	898	3,021	2,290
Income tax expense on other income and expenses	(353)	(207)	(1,210)	(1,077)
Net other income	2,056	2,578	7,667	13,138
Interest expense:
Interest expense	11,891	11,737	34,972	33,165
Allowance for borrowed funds used during construction	(572)	(506)	(1,724)	(1,253)
Net interest expense	11,319	11,231	33,248	31,912
Net income	55,683	62,499	75,792	97,543
Net (loss) income attributable to noncontrolling interests	(189)	70	(650)	(79)
Net income attributable to California Water Service Group	$ 55,872	$ 62,429	$ 76,442	$ 97,622
Earnings per share of common stock:
Basic (in dollars per share)	$ 1.03	$ 1.20	$ 1.41	$ 1.91
Diluted (in dollars per share)	$ 1.03	$ 1.20	$ 1.41	$ 1.91
Weighted average shares outstanding:
Basic (in shares)	54,007	51,823	54,063	51,119
Diluted (in shares)	54,042	51,823	54,104	51,119