Condensed Consolidating Financial Statements (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income	$ 17,170	$ 13,510	$ 11,694	$ 12,437
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization			33,162	30,088
Changes in value of life insurance contracts			(721)	(504)
Other changes in noncurrent assets and liabilities			24,128	1,350
Changes in operating assets and liabilities			(25,079)	(6,595)
Net cash provided by operating activities			43,184	36,776
Investing activities:
Utility plant expenditures			(57,047)	(66,190)
Purchase of life insurance contracts			(1,707)	(1,608)
Changes in restricted cash and other changes, net			313	1,079
Net cash used in investing activities			(58,441)	(66,719)
Financing Activities:
Short-term borrowings			39,400	32,615
Repayment of short-term borrowings			(5,000)	(93,275)
Proceeds from long-term debt				48
Repayment of long-term debt			(4,163)	(2,553)
Advances and contributions in aid for construction			5,950	5,006
Refunds of advances for construction			(3,203)	(3,512)
Dividends paid to non-affiliates			(15,527)	(14,343)
Issuance of common stock, net				105,835
Net cash provided by financing activities			17,457	29,821
Change in cash and cash equivalents			2,200	(122)
Cash and cash equivalents at beginning of period			27,506	38,790
Cash and cash equivalents at end of period	29,706	38,668	29,706	38,668
Consolidating Adjustments
Operating activities:
Net income	(16,969)	(13,275)	(11,272)	(12,045)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity earnings of subsidiaries	16,985	13,291	11,304	12,078
Dividends received from affiliates			(15,527)	(14,343)
Depreciation and amortization			(53)	(56)
Other changes in noncurrent assets and liabilities			21	23
Net cash provided by operating activities			(15,527)	(14,343)
Investing activities:
Investment in affiliates				35,000
Net changes in affiliate advances			5,083	6,876
Repayment of affiliates long-term debt				(8,401)
Proceeds from affiliates long-term debt			(462)
Net cash used in investing activities			4,621	33,475
Financing Activities:
Net changes in affiliate advances			(5,083)	(6,876)
Repayment of affiliates long-term borrowings			462	8,401
Dividends paid to affiliates			15,527	14,343
Investment from affiliates				(35,000)
Net cash provided by financing activities			10,906	(19,132)
Parent Company
Operating activities:
Net income	17,170	13,510	11,694	12,437
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity earnings of subsidiaries	(16,985)	(13,291)	(11,304)	(12,078)
Dividends received from affiliates			15,527	14,343
Depreciation and amortization			100
Other changes in noncurrent assets and liabilities			1,570	108
Changes in operating assets and liabilities			(249)	(514)
Net cash provided by operating activities			17,338	14,296
Investing activities:
Investment in affiliates				(35,000)
Net changes in affiliate advances			(6,175)	(7,294)
Repayment of affiliates long-term debt				605
Proceeds from affiliates long-term debt			462
Net cash used in investing activities			(5,713)	(41,689)
Financing Activities:
Short-term borrowings			4,400	12,615
Repayment of short-term borrowings			(5,000)	(68,275)
Net changes in affiliate advances			(47)	758
Repayment of affiliates long-term borrowings				(7,796)
Dividends paid to non-affiliates			(15,527)	(14,343)
Issuance of common stock, net				105,835
Net cash provided by financing activities			(16,174)	28,794
Change in cash and cash equivalents			(4,549)	1,401
Cash and cash equivalents at beginning of period			5,280	1,470
Cash and cash equivalents at end of period	731	2,871	731	2,871
Cal Water
Operating activities:
Net income	17,522	14,048	13,002	13,791
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization			30,852	28,350
Changes in value of life insurance contracts			(721)	(504)
Other changes in noncurrent assets and liabilities			23,088	883
Changes in operating assets and liabilities			(26,137)	(7,765)
Net cash provided by operating activities			40,084	34,755
Investing activities:
Utility plant expenditures			(53,437)	(57,764)
Net changes in affiliate advances			1,092	(324)
Repayment of affiliates long-term debt				7,796
Purchase of life insurance contracts			(1,707)	(1,608)
Changes in restricted cash and other changes, net			313	1,079
Net cash used in investing activities			(53,739)	(50,821)
Financing Activities:
Short-term borrowings			35,000	20,000
Repayment of short-term borrowings				(25,000)
Repayment of long-term debt				(2,230)
Net changes in affiliate advances			1,087	(892)
Repayment of long-term debt			(2,607)
Advances and contributions in aid for construction			5,427	4,989
Refunds of advances for construction			(3,158)	(3,467)
Dividends paid to affiliates			(15,238)	(12,889)
Investment from affiliates				35,000
Net cash provided by financing activities			20,511	15,511
Change in cash and cash equivalents			6,856	(555)
Cash and cash equivalents at beginning of period			20,790	34,609
Cash and cash equivalents at end of period	27,646	34,054	27,646	34,054
All Other Subsidiaries
Operating activities:
Net income	(553)	(773)	(1,730)	(1,746)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization			2,263	1,794
Other changes in noncurrent assets and liabilities			(551)	336
Changes in operating assets and liabilities			1,307	1,684
Net cash provided by operating activities			1,289	2,068
Investing activities:
Utility plant expenditures			(3,610)	(8,426)
Net changes in affiliate advances				742
Net cash used in investing activities			(3,610)	(7,684)
Financing Activities:
Proceeds from long-term debt				48
Repayment of long-term debt				(323)
Net changes in affiliate advances			4,043	7,010
Repayment of affiliates long-term borrowings			(462)	(605)
Repayment of long-term debt			(1,556)
Advances and contributions in aid for construction			523	17
Refunds of advances for construction			(45)	(45)
Dividends paid to affiliates			(289)	(1,454)
Net cash provided by financing activities			2,214	4,648
Change in cash and cash equivalents			(107)	(968)
Cash and cash equivalents at beginning of period			1,436	2,711
Cash and cash equivalents at end of period	$ 1,329	$ 1,743	$ 1,329	$ 1,743