Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities:
Net income	$ 20,878	$ 24,406	$ 15,171
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	32,709	29,756	27,017
Deferred income taxes	16,458	8,077	6,305
Share-based compensation	651	812	897
Gain on sale of California Water Service Group stock	0	(18,966)	0
Impairment of real estate investment	0	3,597	0
Loss on sale of utility property	23	0	0
Changes in operating assets and liabilities:
Accounts receivable and accrued unbilled utility revenue	(2,470)	(2,197)	1,670
Accounts payable, purchased power and other current liabilities	(133)	887	(464)
Accrued groundwater extraction charges and purchased water	1,430	(137)	(761)
Tax receivable and accrued taxes	(1,102)	(8,528)	2,011
Accrued interest	132	265	413
Accrued payroll	49	316	(962)
Prepaid expenses and materials and supplies	(127)	128	(365)
Postretirement benefits	(37)	(2,566)	3,034
Other current asset	(5,740)	0	0
Other noncurrent assets and noncurrent liabilities	1,855	1,166	398
Other charges, net	(372)	151	182
Net cash provided by operating activities	64,204	37,167	54,546
Investing activities:
Company funded	(62,439)	(95,536)	(55,803)
Contributions in aid of construction	(7,311)	(4,364)	(1,457)
Additions to real estate investment	(156)	(4,540)	0
Cost to retire utility plant, net of salvage	(1,816)	(757)	(459)
Payments for business/asset acquisition and water rights	(4,040)	(3,504)	(6,436)
Proceeds from sale of California Water Service Group stock	0	33,938	0
Proceeds from sale of utility property	43	0	0
Net cash used in investing activities	(75,719)	(74,763)	(64,155)
Financing activities:
Borrowings from line of credit	17,600	62,300	14,100
Repayments of line of credit	(21,600)	(64,100)	(26,700)
Long-term borrowings	50,000	50,000	30,000
Repayments of long-term borrowings	(1,094)	(790)	(749)
Debt issuance costs	(87)	(856)	0
Dividends paid	(12,823)	(12,603)	(12,202)
Exercise of stock options and similar instruments	564	692	551
Tax benefits realized from share options exercised	7	41	74
Receipts of advances and contributions in aid of construction	6,149	5,428	4,846
Refund of advances for construction	(2,197)	(2,202)	(2,301)
Net cash provided by financing activities	36,519	37,910	7,619
Net change in cash and cash equivalents	25,004	314	(1,990)
Cash and cash equivalents, beginning of year	1,730	1,416	3,406
Cash and cash equivalents, end of year	26,734	1,730	1,416
Cash paid (received) during the year for:
Interest	20,307	18,070	15,609
Income taxes	(2,930)	15,326	2,255
Supplemental disclosure of non-cash activities:
(Decrease) increase in accrued payables	1,971	(1,389)	1,142
Utility property installed by developers	567	341	1,457
Obligations (relieved) incurred related to acquisition of certain water service assets	$ (726)	$ 0	$ 1,389