CONDENSED CONSOLIDATING FINANCIAL STATEMENTS (Details 3) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Consolidating Financial Statements
Operating revenue	$ 138,426	$ 183,543	$ 144,414	$ 121,985	$ 137,384	$ 191,184	$ 158,416	$ 110,515	$ 588,368	$ 597,499	$ 584,103
Operations:
Purchased water									168,557	177,884	183,046
Purchased power									27,890	33,159	32,220
Pump taxes									11,479	12,898	10,795
Administrative and general									113,110	97,373	98,055
Other									67,248	65,807	69,738
Maintenance									21,463	19,854	17,368
Depreciation and amortization									61,381	61,217	58,320
Income tax (benefit) expense									24,528	26,727	19,047
Property and other taxes									21,559	20,733	21,509
Total operating expenses									517,215	515,652	510,098
Net operating income	$ 14,962	$ 32,201	$ 16,493	$ 7,497	$ 16,569	$ 40,834	$ 23,292	$ 1,152	71,153	81,847	74,005
Other income and expenses:
Non-regulated revenue									15,624	17,318	14,795
Non-regulated expense									(14,044)	(14,285)	(11,265)
Gain on sale of non-utility property									315	51	0
Income tax (expense) on other income and expenses									(761)	(1,245)	(1,422)
Net other income									1,134	1,839	2,108
Interest expense:
Interest expense									29,185	28,483	30,897
Less: capitalized interest									(1,915)	(1,535)	(2,038)
Net interest expense									27,270	26,948	28,859
Equity earnings of subsidiaries									0	0	0
Net income									45,017	56,738	47,254
Consolidating Adjustments
Condensed Consolidating Financial Statements
Operating revenue									0	0	0
Operations:
Purchased water									0	0	0
Purchased power									0	0	0
Pump taxes									0	0	0
Administrative and general									0	0	0
Other									(505)	(505)	(504)
Maintenance									0	0	0
Depreciation and amortization									(101)	(107)	(112)
Income tax (benefit) expense									1,008	964	1,341
Property and other taxes									0	0	0
Total operating expenses									402	352	725
Net operating income									(402)	(352)	(725)
Other income and expenses:
Non-regulated revenue									(2,322)	(2,170)	(3,052)
Non-regulated expense									0	0	0
Gain on sale of non-utility property									0	0
Income tax (expense) on other income and expenses									967	920	1,296
Net other income									(1,355)	(1,250)	(1,756)
Interest expense:
Interest expense									(1,817)	(1,666)	(2,547)
Less: capitalized interest									0	0	0
Net interest expense									(1,817)	(1,666)	(2,547)
Equity earnings of subsidiaries									(44,516)	(56,064)	(46,519)
Net income									(44,456)	(56,000)	(46,453)
Parent Company
Condensed Consolidating Financial Statements
Operating revenue									0	0	0
Operations:
Purchased water									0	0	0
Purchased power									0	0	0
Pump taxes									0	0	0
Administrative and general									0	66	69
Other									0	0	0
Maintenance									0	0	0
Depreciation and amortization									228	214	56
Income tax (benefit) expense									(388)	(275)	(304)
Property and other taxes									0	0	0
Total operating expenses									(160)	5	(179)
Net operating income									160	(5)	179
Other income and expenses:
Non-regulated revenue									1,787	1,811	2,323
Non-regulated expense									0	0	(337)
Gain on sale of non-utility property									0	0
Income tax (expense) on other income and expenses									(728)	(738)	(809)
Net other income									1,059	1,073	1,177
Interest expense:
Interest expense									718	394	621
Less: capitalized interest									0	0	0
Net interest expense									718	394	621
Equity earnings of subsidiaries									44,516	56,064	46,519
Net income									45,017	56,738	47,254
Cal Water
Condensed Consolidating Financial Statements
Operating revenue									552,202	564,508	552,327
Operations:
Purchased water									168,157	177,561	182,503
Purchased power									20,282	24,089	22,932
Pump taxes									11,479	12,898	10,795
Administrative and general									101,244	87,130	87,620
Other									61,154	59,291	63,237
Maintenance									20,659	19,141	16,654
Depreciation and amortization									56,911	56,836	54,886
Income tax (benefit) expense									23,964	27,286	19,890
Property and other taxes									18,848	18,086	18,679
Total operating expenses									482,698	482,318	477,196
Net operating income									69,504	82,190	75,131
Other income and expenses:
Non-regulated revenue									14,460	16,085	13,606
Non-regulated expense									(12,870)	(13,086)	(9,465)
Gain on sale of non-utility property									315	51
Income tax (expense) on other income and expenses									(776)	(1,243)	(1,687)
Net other income									1,129	1,807	2,454
Interest expense:
Interest expense									28,450	27,777	30,238
Less: capitalized interest									(1,873)	(1,460)	(1,662)
Net interest expense									26,577	26,317	28,576
Equity earnings of subsidiaries									0	0	0
Net income									44,056	57,680	49,009
All Other Subsidiaries
Condensed Consolidating Financial Statements
Operating revenue									36,166	32,991	31,776
Operations:
Purchased water									400	323	543
Purchased power									7,608	9,070	9,288
Pump taxes									0	0	0
Administrative and general									11,866	10,177	10,366
Other									6,599	7,021	7,005
Maintenance									804	713	714
Depreciation and amortization									4,343	4,274	3,490
Income tax (benefit) expense									(56)	(1,248)	(1,880)
Property and other taxes									2,711	2,647	2,830
Total operating expenses									34,275	32,977	32,356
Net operating income									1,891	14	(580)
Other income and expenses:
Non-regulated revenue									1,699	1,592	1,918
Non-regulated expense									(1,174)	(1,199)	(1,463)
Gain on sale of non-utility property									0	0
Income tax (expense) on other income and expenses									(224)	(184)	(222)
Net other income									301	209	233
Interest expense:
Interest expense									1,834	1,978	2,585
Less: capitalized interest									(42)	(75)	(376)
Net interest expense									1,792	1,903	2,209
Equity earnings of subsidiaries									0	0	0
Net income									$ 400	$ (1,680)	$ (2,556)