CONDENSED CONSOLIDATING FINANCIAL STATEMENTS (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Consolidating Financial Statements
Operating revenue	$ 137,384	$ 191,184	$ 158,416	$ 110,515	$ 133,700	$ 184,404	$ 154,555	$ 111,444	$ 597,499	$ 584,103	$ 559,966
Operations:
Purchased water									177,884	183,046	161,336
Purchased power									33,159	32,220	31,027
Pump taxes									12,898	10,795	10,336
Administrative and general									97,373	98,055	93,927
Other									65,807	69,738	77,104
Maintenance									19,854	17,368	19,142
Depreciation and amortization									61,217	58,320	54,668
Income tax (benefit)									26,727	19,047	19,356
Taxes other than income taxes									20,733	21,509	19,227
Total operating expenses									515,652	510,098	486,123
Net operating income	16,569	40,834	23,292	1,152	11,648	35,804	20,783	5,770	81,847	74,005	73,843
Other Income and Expenses:
Non-regulated revenue									17,318	14,795	16,686
Non-regulated expenses									(14,285)	(11,265)	(11,553)
Gain on sale on non-utility property									51		84
Income tax (expense) benefit on other income and expense									(1,245)	(1,422)	(2,096)
Net other income									1,839	2,108	3,121
Interest:
Interest expense									28,483	30,897	31,537
Less: capitalized interest									(1,535)	(2,038)	(3,401)
Net interest expense									26,948	28,859	28,136
Net income									56,738	47,254	48,828
Consolidating Adjustments
Operations:
Other									(505)	(504)	(504)
Depreciation and amortization									(107)	(112)	(118)
Income tax (benefit)									964	1,341	1,322
Total operating expenses									352	725	700
Net operating income									(352)	(725)	(700)
Other Income and Expenses:
Non-regulated revenue									(2,170)	(3,052)	(2,857)
Gain on sale on non-utility property											3
Income tax (expense) benefit on other income and expense									920	1,296	1,273
Net other income									(1,250)	(1,756)	(1,581)
Interest:
Interest expense									(1,666)	(2,547)	(2,353)
Net interest expense									(1,666)	(2,547)	(2,353)
Equity earnings of subsidiaries									(56,064)	(46,519)	(48,538)
Net income									(56,000)	(46,453)	(48,466)
Parent Company
Operations:
Administrative and general									66	69
Depreciation and amortization									214	56
Income tax (benefit)									(275)	(304)	(583)
Total operating expenses									5	(179)	(583)
Net operating income									(5)	179	583
Other Income and Expenses:
Non-regulated revenue									1,811	2,323	1,919
Non-regulated expenses										(337)
Income tax (expense) benefit on other income and expense									(738)	(809)	(782)
Net other income									1,073	1,177	1,137
Interest:
Interest expense									394	621	1,430
Net interest expense									394	621	1,430
Equity earnings of subsidiaries									56,064	46,519	48,538
Net income									56,738	47,254	48,828
Cal Water
Condensed Consolidating Financial Statements
Operating revenue									564,508	552,327	527,449
Operations:
Purchased water									177,561	182,503	160,913
Purchased power									24,089	22,932	21,435
Pump taxes									12,898	10,795	10,336
Administrative and general									87,130	87,620	84,399
Other									59,291	63,237	70,864
Maintenance									19,141	16,654	18,478
Depreciation and amortization									56,836	54,886	52,012
Income tax (benefit)									27,286	19,890	18,992
Taxes other than income taxes									18,086	18,679	16,630
Total operating expenses									482,318	477,196	454,059
Net operating income									82,190	75,131	73,390
Other Income and Expenses:
Non-regulated revenue									16,085	13,606	15,204
Non-regulated expenses									(13,086)	(9,465)	(9,588)
Gain on sale on non-utility property									51		81
Income tax (expense) benefit on other income and expense									(1,243)	(1,687)	(2,321)
Net other income									1,807	2,454	3,376
Interest:
Interest expense									27,777	30,238	30,328
Less: capitalized interest									(1,460)	(1,662)	(2,334)
Net interest expense									26,317	28,576	27,994
Net income									57,680	49,009	48,772
All Other Subsidiaries
Condensed Consolidating Financial Statements
Operating revenue									32,991	31,776	32,517
Operations:
Purchased water									323	543	423
Purchased power									9,070	9,288	9,592
Administrative and general									10,177	10,366	9,528
Other									7,021	7,005	6,744
Maintenance									713	714	664
Depreciation and amortization									4,274	3,490	2,774
Income tax (benefit)									(1,248)	(1,880)	(375)
Taxes other than income taxes									2,647	2,830	2,597
Total operating expenses									32,977	32,356	31,947
Net operating income									14	(580)	570
Other Income and Expenses:
Non-regulated revenue									1,592	1,918	2,420
Non-regulated expenses									(1,199)	(1,463)	(1,965)
Income tax (expense) benefit on other income and expense									(184)	(222)	(266)
Net other income									209	233	189
Interest:
Interest expense									1,978	2,585	2,132
Less: capitalized interest									(75)	(376)	(1,067)
Net interest expense									1,903	2,209	1,065
Net income									$ (1,680)	$ (2,556)	$ (306)