Condensed Consolidating Financial Statements (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Condensed Consolidating Financial Statements
Operating revenue	$ 152,445	$ 144,414	$ 274,172	$ 266,399
Operations:
Water production costs	57,589	53,022	98,658	98,224
Administrative and general	23,366	26,637	51,193	54,332
Other operations	18,903	17,512	38,205	33,355
Maintenance	5,934	5,326	11,997	9,783
Depreciation and amortization	15,842	15,354	31,888	30,673
Income tax (benefit) expense	6,870	5,102	5,945	5,715
Property and other taxes	5,407	4,968	11,482	10,327
Total operating (income) expense	133,911	127,921	249,368	242,409
Net operating income (loss)	18,534	16,493	24,804	23,990
Other income and expenses:
Non-regulated revenue	3,764	3,479	7,192	6,726
Non-regulated expenses	(2,809)	(3,504)	(5,789)	(5,747)
Income tax (expense) benefit on other income and expenses	(384)	10	(565)	(393)
Net other income (loss)	571	(15)	838	586
Interest:
Interest expense	8,434	7,061	16,499	14,130
Less: capitalized interest	(837)	(428)	(1,567)	(974)
Net interest expense	7,597	6,633	14,932	13,156
Equity earnings of subsidiaries	0	0	0	0
Net Income	11,508	9,845	10,710	11,420
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	(84)	(127)	(210)	(253)
Maintenance	0	0	0	0
Depreciation and amortization	(24)	(26)	(48)	(51)
Income tax (benefit) expense	238	298	495	502
Property and other taxes	0	0	0	0
Total operating (income) expense	130	145	237	198
Net operating income (loss)	(130)	(145)	(237)	(198)
Other income and expenses:
Non-regulated revenue	(560)	(680)	(1,166)	(1,158)
Non-regulated expenses	0	0	0	0
Income tax (expense) benefit on other income and expenses	228	287	475	481
Net other income (loss)	(332)	(393)	(691)	(677)
Interest:
Interest expense	(476)	(553)	(956)	(905)
Less: capitalized interest	0	0	0	0
Net interest expense	(476)	(553)	(956)	(905)
Equity earnings of subsidiaries	(11,371)	(9,751)	(10,434)	(11,156)
Net Income	(11,357)	(9,736)	(10,406)	(11,126)
Parent Company
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	0	0	0	0
Maintenance	0	0	0	0
Depreciation and amortization	57	57	114	114
Income tax (benefit) expense	(93)	(119)	(187)	(187)
Property and other taxes	0	0	0	0
Total operating (income) expense	(36)	(62)	(73)	(73)
Net operating income (loss)	36	62	73	73
Other income and expenses:
Non-regulated revenue	462	455	926	909
Non-regulated expenses	0	0	0	0
Income tax (expense) benefit on other income and expenses	(188)	(183)	(377)	(368)
Net other income (loss)	274	272	549	541
Interest:
Interest expense	173	240	346	350
Less: capitalized interest	0	0	0	0
Net interest expense	173	240	346	350
Equity earnings of subsidiaries	11,371	9,751	10,434	11,156
Net Income	11,508	9,845	10,710	11,420
Cal Water
Condensed Consolidating Financial Statements
Operating revenue	142,342	135,440	255,369	249,947
Operations:
Water production costs	55,643	51,044	94,888	94,420
Administrative and general	20,667	23,796	45,610	48,651
Other operations	17,365	16,033	35,091	30,303
Maintenance	5,692	5,162	11,532	9,426
Depreciation and amortization	14,735	14,225	29,650	28,428
Income tax (benefit) expense	6,228	4,886	5,191	5,816
Property and other taxes	4,669	4,304	10,059	9,054
Total operating (income) expense	124,999	119,450	232,021	226,098
Net operating income (loss)	17,343	15,990	23,348	23,849
Other income and expenses:
Non-regulated revenue	3,439	3,312	6,635	6,185
Non-regulated expenses	(2,547)	(3,193)	(5,252)	(5,225)
Income tax (expense) benefit on other income and expenses	(364)	(48)	(564)	(391)
Net other income (loss)	528	71	819	569
Interest:
Interest expense	8,263	6,922	16,162	13,782
Less: capitalized interest	(820)	(417)	(1,534)	(950)
Net interest expense	7,443	6,505	14,628	12,832
Equity earnings of subsidiaries	0	0	0	0
Net Income	10,428	9,556	9,539	11,586
All Other Subsidiaries
Condensed Consolidating Financial Statements
Operating revenue	10,103	8,974	18,803	16,452
Operations:
Water production costs	1,946	1,978	3,770	3,804
Administrative and general	2,699	2,841	5,583	5,681
Other operations	1,622	1,606	3,324	3,305
Maintenance	242	164	465	357
Depreciation and amortization	1,074	1,098	2,172	2,182
Income tax (benefit) expense	497	37	446	(416)
Property and other taxes	738	664	1,423	1,273
Total operating (income) expense	8,818	8,388	17,183	16,186
Net operating income (loss)	1,285	586	1,620	266
Other income and expenses:
Non-regulated revenue	423	392	797	790
Non-regulated expenses	(262)	(311)	(537)	(522)
Income tax (expense) benefit on other income and expenses	(60)	(46)	(99)	(115)
Net other income (loss)	101	35	161	153
Interest:
Interest expense	474	452	947	903
Less: capitalized interest	(17)	(11)	(33)	(24)
Net interest expense	457	441	914	879
Equity earnings of subsidiaries	0	0	0	0
Net Income	$ 929	$ 180	$ 867	$ (460)