Condensed Consolidating Financial Statements (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Consolidating Financial Statements
Operating revenue	$ 122,036	$ 121,727
Operations:
Water production costs	42,068	41,069
Administrative and general	25,249	27,827
Other operations	16,124	19,302
Maintenance	6,112	6,063
Depreciation and amortization	19,201	16,046
Income tax (benefit) expense	(884)	(925)
Property and other taxes	6,116	6,075
Total operating expenses	113,986	115,457
Net operating income (loss)	8,050	6,270
Other income and expenses:
Non-regulated revenue	3,462	3,428
Non-regulated expenses	(2,054)	(2,980)
Allowance for equity funds used during construction (Note 2)	779	0
Income tax expense on other income and expenses	(889)	(181)
Net other income	1,298	267
Interest:
Interest expense	8,710	8,065
Allowance for borrowed funds used during construction (Note 2)	(494)	(730)
Net interest expense	8,216	7,335
Equity earnings of subsidiaries	0	0
Net income (loss)	1,132	(798)
Consolidating Adjustments
Condensed Consolidating Financial Statements
Operating revenue	0	0
Operations:
Water production costs	0	0
Administrative and general	0	0
Other operations	(126)	(126)
Maintenance	0	0
Depreciation and amortization	(23)	(24)
Income tax (benefit) expense	257	257
Property and other taxes	0	0
Total operating expenses	108	107
Net operating income (loss)	(108)	(107)
Other income and expenses:
Non-regulated revenue	(608)	(606)
Non-regulated expenses	0	0
Allowance for equity funds used during construction (Note 2)	0
Income tax expense on other income and expenses	248	247
Net other income	(360)	(359)
Interest:
Interest expense	(481)	(480)
Allowance for borrowed funds used during construction (Note 2)	0	0
Net interest expense	(481)	(480)
Equity earnings of subsidiaries	(998)	937
Net income (loss)	(985)	951
Parent Company
Condensed Consolidating Financial Statements
Operating revenue	0	0
Operations:
Water production costs	0	0
Administrative and general	0	0
Other operations	0	0
Maintenance	0	0
Depreciation and amortization	23	57
Income tax (benefit) expense	(103)	(94)
Property and other taxes	(4)	0
Total operating expenses	(84)	(37)
Net operating income (loss)	84	37
Other income and expenses:
Non-regulated revenue	481	464
Non-regulated expenses	0	0
Allowance for equity funds used during construction (Note 2)	0
Income tax expense on other income and expenses	(196)	(189)
Net other income	285	275
Interest:
Interest expense	235	173
Allowance for borrowed funds used during construction (Note 2)	0	0
Net interest expense	235	173
Equity earnings of subsidiaries	998	(937)
Net income (loss)	1,132	(798)
Cal Water
Condensed Consolidating Financial Statements
Operating revenue	113,342	113,027
Operations:
Water production costs	40,189	39,245
Administrative and general	22,476	24,943
Other operations	14,400	17,726
Maintenance	5,906	5,840
Depreciation and amortization	18,111	14,915
Income tax (benefit) expense	(946)	(1,037)
Property and other taxes	5,412	5,390
Total operating expenses	105,548	107,022
Net operating income (loss)	7,794	6,005
Other income and expenses:
Non-regulated revenue	3,135	3,196
Non-regulated expenses	(1,747)	(2,705)
Allowance for equity funds used during construction (Note 2)	779
Income tax expense on other income and expenses	(883)	(200)
Net other income	1,284	291
Interest:
Interest expense	8,470	7,899
Allowance for borrowed funds used during construction (Note 2)	(476)	(714)
Net interest expense	7,994	7,185
Equity earnings of subsidiaries	0	0
Net income (loss)	1,084	(889)
All Other Subsidiaries
Condensed Consolidating Financial Statements
Operating revenue	8,694	8,700
Operations:
Water production costs	1,879	1,824
Administrative and general	2,773	2,884
Other operations	1,850	1,702
Maintenance	206	223
Depreciation and amortization	1,090	1,098
Income tax (benefit) expense	(92)	(51)
Property and other taxes	708	685
Total operating expenses	8,414	8,365
Net operating income (loss)	280	335
Other income and expenses:
Non-regulated revenue	454	374
Non-regulated expenses	(307)	(275)
Allowance for equity funds used during construction (Note 2)	0
Income tax expense on other income and expenses	(58)	(39)
Net other income	89	60
Interest:
Interest expense	486	473
Allowance for borrowed funds used during construction (Note 2)	(18)	(16)
Net interest expense	468	457
Equity earnings of subsidiaries	0	0
Net income (loss)	$ (99)	$ (62)