Condensed Consolidating Financial Statements (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Consolidating Financial Statements
Operating revenue	$ 183,543	$ 191,184	$ 449,942	$ 460,115
Operations:
Water production costs	60,437	66,980	158,661	174,297
Administrative and general	30,737	23,765	85,069	72,702
Other operations	17,872	15,692	51,227	48,072
Maintenance	5,952	4,800	15,735	14,793
Depreciation and amortization	15,342	14,648	46,015	46,788
Income tax (benefit) expense	15,293	19,233	21,008	22,584
Property and other taxes	5,709	5,232	16,036	15,601
Total operating expenses	151,342	150,350	393,751	394,837
Net operating income	32,201	40,834	56,191	65,278
Other Income and Expenses:
Non-regulated revenue	3,814	4,409	10,540	12,163
Non-regulated expenses, net	(4,454)	(4,812)	(10,201)	(11,184)
Income tax (expense) benefit on other income and expense	262	169	(131)	(391)
Net other loss	(378)	(234)	208	588
Interest:
Interest expense	7,201	7,221	21,331	21,373
Less: capitalized interest	(498)	(271)	(1,472)	(851)
Net interest expense	6,703	6,950	19,859	20,522
Equity earnings of subsidiaries	0	0	0	0
Net Income	25,120	33,650	36,540	45,344
Consolidating Adjustments
Condensed Consolidating Financial Statements
Operating revenue	0	0	0	0
Operations:
Water production costs	0	0	0	0
Administrative and general	0	0	0	0
Other operations	(125)	(126)	(378)	(378)
Maintenance	0	0	0	0
Depreciation and amortization	(25)	(27)	(76)	(80)
Income tax (benefit) expense	254	287	756	741
Property and other taxes	0	0	0	0
Total operating expenses	104	134	302	283
Net operating income	(104)	(134)	(302)	(283)
Other Income and Expenses:
Non-regulated revenue	(570)	(512)	(1,728)	(1,659)
Non-regulated expenses, net	0	0	0	0
Income tax (expense) benefit on other income and expense	244	276	725	708
Net other loss	(326)	(236)	(1,003)	(951)
Interest:
Interest expense	(445)	(385)	(1,350)	(1,281)
Less: capitalized interest	0	0	0	0
Net interest expense	(445)	(385)	(1,350)	(1,281)
Equity earnings of subsidiaries	(25,012)	(33,499)	(36,168)	(44,803)
Net Income	(24,997)	(33,484)	(36,123)	(44,756)
Parent Company
Condensed Consolidating Financial Statements
Operating revenue	0	0	0	0
Operations:
Water production costs	0	0	0	0
Administrative and general	0	34	0	67
Other operations	0	0	0	0
Maintenance	0	0	0	0
Depreciation and amortization	57	57	171	157
Income tax (benefit) expense	(107)	(79)	(294)	(184)
Property and other taxes	0	0	0	0
Total operating expenses	(50)	12	(123)	40
Net operating income	50	(12)	123	(40)
Other Income and Expenses:
Non-regulated revenue	444	448	1,353	1,365
Non-regulated expenses, net	0	0	0	0
Income tax (expense) benefit on other income and expense	(181)	(182)	(549)	(556)
Net other loss	263	266	804	809
Interest:
Interest expense	205	103	555	228
Less: capitalized interest	0	0	0	0
Net interest expense	205	103	555	228
Equity earnings of subsidiaries	25,012	33,499	36,168	44,803
Net Income	25,120	33,650	36,540	45,344
Cal Water
Condensed Consolidating Financial Statements
Operating revenue	172,425	180,768	422,372	434,857
Operations:
Water production costs	58,173	64,332	152,593	167,214
Administrative and general	27,620	21,282	76,271	65,144
Other operations	16,329	14,161	46,632	43,186
Maintenance	5,722	4,620	15,148	14,276
Depreciation and amortization	14,231	13,692	42,659	43,607
Income tax (benefit) expense	14,638	18,632	20,454	22,713
Property and other taxes	4,910	4,409	13,964	13,552
Total operating expenses	141,623	141,128	367,721	369,692
Net operating income	30,802	39,640	54,651	65,165
Other Income and Expenses:
Non-regulated revenue	3,489	4,027	9,674	11,264
Non-regulated expenses, net	(4,058)	(4,538)	(9,283)	(10,286)
Income tax (expense) benefit on other income and expense	232	207	(159)	(399)
Net other loss	(337)	(304)	232	579
Interest:
Interest expense	6,969	7,030	20,751	20,974
Less: capitalized interest	(488)	(252)	(1,438)	(790)
Net interest expense	6,481	6,778	19,313	20,184
Equity earnings of subsidiaries	0	0	0	0
Net Income	23,984	32,558	35,570	45,560
All Other Subsidiaries
Condensed Consolidating Financial Statements
Operating revenue	11,118	10,416	27,570	25,258
Operations:
Water production costs	2,264	2,648	6,068	7,083
Administrative and general	3,117	2,449	8,798	7,491
Other operations	1,668	1,657	4,973	5,264
Maintenance	230	180	587	517
Depreciation and amortization	1,079	926	3,261	3,104
Income tax (benefit) expense	508	393	92	(686)
Property and other taxes	799	823	2,072	2,049
Total operating expenses	9,665	9,076	25,851	24,822
Net operating income	1,453	1,340	1,719	436
Other Income and Expenses:
Non-regulated revenue	451	446	1,241	1,193
Non-regulated expenses, net	(396)	(274)	(918)	(898)
Income tax (expense) benefit on other income and expense	(33)	(132)	(148)	(144)
Net other loss	22	40	175	151
Interest:
Interest expense	472	473	1,375	1,452
Less: capitalized interest	(10)	(19)	(34)	(61)
Net interest expense	462	454	1,341	1,391
Equity earnings of subsidiaries	0	0	0	0
Net Income	$ 1,013	$ 926	$ 553	$ (804)