CONDENSED CONSOLIDATING FINANCIAL STATEMENTS (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Net income (loss)	$ 47,254	$ 48,828	$ 37,712
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	60,250	56,866	51,981
Change in value of life insurance contracts	(1,878)	(2,504)	1,876
Stock-based compensation	1,832	1,442	1,300
Gain on sale of non-utility property		(84)	(62)
Changes in deferred income taxes	9,800	34,133	2,723
Other changes in noncurrent assets and liabilities	11,325	(8,825)	393
Changes in operating assets and liabilities	(4,410)	2,058	15,349
Net cash provided by operating activities	124,173	131,914	111,272
Investing activities:
Utility plant expenditures	(122,988)	(127,681)	(118,546)
Proceeds from sale of non-utility assets		85	64
Purchase of life insurance	(3,281)	(3,294)	(1,744)
Restricted cash decrease (increase)	1,073	1,959	(3,042)
Net cash used in investing activities	(125,196)	(128,931)	(123,268)
Financing Activities:
Short-term borrowings	70,615	94,335	23,390
Repayment of short-term borrowings	(113,275)	(52,000)
Proceeds from long-term debt, net of issuance cost of $1,857	48	124	178
Repayment/Retirement of long-term debt	(47,248)	(7,037)	(2,963)
Advances and contributions in aid for construction	10,563	6,966	7,231
Refunds of advances for construction	(6,922)	(7,397)	(6,205)
Dividends paid to non-affiliates	(29,619)	(26,387)	(25,674)
Issuance of common stock	105,577
Issuance of common stock	110,688		965
Net cash (used in) provided by financing activities	(10,261)	8,604	(3,078)
Change in cash and cash equivalents	(11,284)	11,587	(15,074)
Cash and cash equivalents at beginning of year	38,790	27,203	42,277
Cash and cash equivalents at end of year	27,506	38,790	27,203
Parent Company
Operating activities:
Net income (loss)	47,254	48,828	37,712
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity earnings of subsidiaries	(46,519)	(48,538)	(37,222)
Dividends received from affiliates	29,619	26,387	25,674
Depreciation and amortization	56	56	51
Stock-based compensation	1,832	1,442	1,300
Other changes in noncurrent assets and liabilities	(76)	102	(299)
Changes in operating assets and liabilities	544	(170)	582
Net cash provided by operating activities	32,710	28,107	27,798
Investing activities:
Utility plant expenditures	(712)	(281)
Investment in affiliates	(35,000)
Affiliate advances	(14,903)	(12,245)	(25,495)
Proceeds from affiliate loans	1,227	552
Reduction of loans to affiliates		(5,675)	962
Net cash used in investing activities	(49,388)	(17,649)	(24,533)
Financing Activities:
Short-term borrowings	20,615	18,335	23,390
Repayment of short-term borrowings	(68,275)	(1,000)
Affiliate advances	(14)	23
Reduction of affiliate long-term borrowings	(7,796)	(48)	(2,045)
Dividends paid to non-affiliates	(29,619)	(26,387)	(25,674)
Issuance of common stock	105,577		965
Net cash (used in) provided by financing activities	20,488	(9,077)	(3,364)
Change in cash and cash equivalents	3,810	1,381	(99)
Cash and cash equivalents at beginning of year	1,470	89	188
Cash and cash equivalents at end of year	5,280	1,470	89
Cal Water
Operating activities:
Net income (loss)	49,009	48,772	38,333
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	56,670	54,040	49,283
Change in value of life insurance contracts	(1,878)	(2,504)	1,876
Gain on sale of non-utility property		(81)	(62)
Changes in deferred income taxes	9,800	34,133	2,723
Other changes in noncurrent assets and liabilities	11,899	(10,367)	(45)
Changes in operating assets and liabilities	226	9,035	11,662
Net cash provided by operating activities	125,726	133,028	103,770
Investing activities:
Utility plant expenditures	(111,819)	(111,636)	(98,410)
Proceeds from sale of non-utility assets		82	64
Affiliate advances	(2,575)	254	1,597
Proceeds from affiliate loans	7,796	48
Reduction of loans to affiliates			45
Purchase of life insurance	(3,281)	(3,294)	(1,744)
Restricted cash decrease (increase)	1,073	1,959	(3,042)
Net cash used in investing activities	(108,806)	(112,587)	(101,490)
Financing Activities:
Short-term borrowings	50,000	76,000
Repayment of short-term borrowings	(45,000)	(51,000)
Affiliate advances	(1,152)	962
Repayment/Retirement of long-term debt	(46,547)	(6,310)	(2,279)
Advances and contributions in aid for construction	10,465	6,883	7,082
Refunds of advances for construction	(6,814)	(7,275)	(6,129)
Dividends paid to affiliates	(26,691)	(23,567)	(22,925)
Investment from affiliates	35,000
Net cash (used in) provided by financing activities	(30,739)	(4,307)	(24,251)
Change in cash and cash equivalents	(13,819)	16,134	(21,971)
Cash and cash equivalents at beginning of year	34,609	18,475	40,446
Cash and cash equivalents at end of year	20,790	34,609	18,475
All Other Subsidiaries
Operating activities:
Net income (loss)	(2,556)	(306)	(1,131)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	3,636	2,888	2,771
Other changes in noncurrent assets and liabilities	(449)	1,307	684
Changes in operating assets and liabilities	(5,275)	(6,723)	3,054
Net cash provided by operating activities	(4,644)	(2,834)	5,378
Investing activities:
Utility plant expenditures	(10,457)	(15,761)	(20,136)
Affiliate advances	1,210	(853)
Reduction of loans to affiliates			2,000
Net cash used in investing activities	(9,247)	(16,614)	(18,136)
Financing Activities:
Affiliate advances	17,434	11,859	23,898
Proceeds from affiliates long-term borrowings		5,675
Reduction of affiliate long-term borrowings	(1,227)	(552)	(962)
Proceeds from long-term debt, net of issuance cost of $1,857	48	124	178
Repayment/Retirement of long-term debt	(701)	(727)	(684)
Advances and contributions in aid for construction	98	83	149
Refunds of advances for construction	(108)	(122)	(76)
Dividends paid to affiliates	(2,928)	(2,820)	(2,749)
Net cash (used in) provided by financing activities	12,616	13,520	19,754
Change in cash and cash equivalents	(1,275)	(5,928)	6,996
Cash and cash equivalents at beginning of year	2,711	8,639	1,643
Cash and cash equivalents at end of year	1,436	2,711	8,639
Consolidating Adjustments
Operating activities:
Net income (loss)	(46,453)	(48,466)	(37,202)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity earnings of subsidiaries	46,519	48,538	37,222
Dividends received from affiliates	(29,619)	(26,387)	(25,674)
Depreciation and amortization	(112)	(118)	(124)
Gain on sale of non-utility property		(3)
Other changes in noncurrent assets and liabilities	(49)	133	53
Changes in operating assets and liabilities	95	(84)	51
Net cash provided by operating activities	(29,619)	(26,387)	(25,674)
Investing activities:
Utility plant expenditures		(3)
Investment in affiliates	35,000
Proceeds from sale of non-utility assets		3
Affiliate advances	16,268	12,844	23,898
Proceeds from affiliate loans	(9,023)	(600)
Reduction of loans to affiliates		5,675	(3,007)
Net cash used in investing activities	42,245	17,919	20,891
Financing Activities:
Affiliate advances	(16,268)	(12,844)	(23,898)
Proceeds from affiliates long-term borrowings		(5,675)
Reduction of affiliate long-term borrowings	9,023	600	3,007
Dividends paid to affiliates	29,619	26,387	25,674
Investment from affiliates	(35,000)
Net cash (used in) provided by financing activities	$ (12,626)	$ 8,468	$ 4,783