CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows From Operating Activities:
Net income	$ 54,148,000	$ 45,859,000	$ 33,197,000
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on CCWC, net of taxes, included in discontinued operations		(2,454,000)
Depreciation and amortization	43,234,000	40,809,000	40,410,000
Net gain on sale of property	(68,000)	(128,000)	(643,000)
Provision for doubtful accounts	1,710,000	938,000	1,069,000
Deferred income taxes and investment tax credits	15,087,000	13,861,000	6,689,000
Stock-based compensation expense	1,931,000	1,520,000	1,482,000
Impairment and other charges	416,000		16,634,000
Other - net	(35,000)	359,000	618,000
Changes in assets and liabilities:
Accounts receivable - customers	(1,773,000)	(2,687,000)	(2,230,000)
Unbilled revenue	1,108,000	3,093,000	(2,509,000)
Other accounts receivable	5,416,000	(2,139,000)	2,345,000
Receivables from the U.S. government	(3,196,000)	(3,789,000)	556,000
Materials and supplies	(2,278,000)	(909,000)	(267,000)
Prepayments and other current assets	(432,000)	2,198,000	(1,193,000)
Regulatory assets - supply cost balancing accounts	11,709,000	18,748,000	20,622,000
Other assets (including other regulatory assets)	(20,139,000)	(26,661,000)	(44,288,000)
Costs and estimated earnings in excess of billings on uncompleted contracts	(3,075,000)	918,000	(15,049,000)
Accounts payable	4,300,000	(2,953,000)	3,154,000
Income taxes receivable/payable	4,169,000	(14,544,000)	(2,678,000)
Billings in excess of costs and estimated earnings on uncompleted contracts	(17,673,000)	4,819,000	7,531,000
Accrued pension and other post-retirement benefits	5,954,000	1,647,000	(542,000)
Other liabilities	981,000	1,662,000	(11,144,000)
Net cash provided	101,494,000	80,167,000	53,764,000
Cash Flows From Investing Activities:
Capital expenditures	(68,104,000)	(80,281,000)	(79,050,000)
Proceeds from the sale of CCWC		29,603,000
Proceeds from sale of property	68,000	144,000	820,000
Net cash used	(68,036,000)	(50,534,000)	(78,230,000)
Cash Flows From Financing Activities:
Proceeds from issuance of Common Shares, net of issuance cost		1,658,000	1,838,000
Proceeds from stock option exercises	13,295,000	2,350,000	857,000
Tax benefits from exercise of stock-based awards	890,000	336,000	111,000
Receipt of advances for and contributions in aid of construction	9,647,000	7,489,000	6,069,000
Refunds on advances for construction	(3,614,000)	(4,136,000)	(3,837,000)
Retirement or repayments of long-term debt	(8,303,000)	(22,380,000)	(701,000)
Proceeds from issuance of long-term debt, net of issuance costs	3,408,000	61,912,000
Net change in notes payable to banks	(2,000,000)	(58,900,000)	43,500,000
Dividends paid	(24,130,000)	(20,552,000)	(19,326,000)
Other	(480,000)	(292,000)	(236,000)
Net cash provided (used)	(11,287,000)	(32,515,000)	28,275,000
Net increase (decrease) in cash and cash equivalents	22,171,000	(2,882,000)	3,809,000
Cash and cash equivalents, beginning of year	1,315,000	5,494,000	1,685,000
Cash and cash equivalents, end of year	23,486,000	1,315,000	5,494,000
Less cash and cash equivalents of discontinued operations			1,297,000
Cash and cash equivalents of continuing operations	23,486,000	1,315,000	4,197,000
GOLDEN STATE WATER COMPANY
Cash Flows From Operating Activities:
Net income	39,220,000	34,822,000	25,110,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	42,046,000	39,921,000	38,843,000
Net gain on sale of property	(65,000)	(128,000)	(640,000)
Provision for doubtful accounts	1,668,000	859,000	1,041,000
Deferred income taxes and investment tax credits	14,713,000	13,805,000	6,688,000
Stock-based compensation expense	1,667,000	1,345,000	1,139,000
Impairment and other charges	416,000		16,634,000
Other - net	(107,000)	(137,000)	255,000
Changes in assets and liabilities:
Accounts receivable - customers	(1,773,000)	(2,687,000)	(2,209,000)
Unbilled revenue	1,108,000	3,093,000	(2,513,000)
Other accounts receivable	1,717,000	361,000	3,664,000
Materials and supplies	(318,000)	(147,000)	(100,000)
Prepayments and other current assets	(452,000)	1,985,000	(757,000)
Regulatory assets - supply cost balancing accounts	11,709,000	18,748,000	20,622,000
Other assets (including other regulatory assets)	(20,056,000)	(26,693,000)	(44,266,000)
Accounts payable	(2,331,000)	1,093,000	(683,000)
Inter-company receivable/payable	277,000	482,000	(75,000)
Income taxes receivable/payable from/to Parent	3,472,000	(12,493,000)	(2,001,000)
Accrued pension and other post-retirement benefits	5,954,000	1,647,000	(542,000)
Other liabilities	1,035,000	1,678,000	(11,205,000)
Net cash provided	99,900,000	77,554,000	49,005,000
Cash Flows From Investing Activities:
Capital expenditures	(66,831,000)	(78,438,000)	(76,964,000)
Proceeds from sale of property	65,000	144,000	817,000
Net cash used	(66,766,000)	(78,294,000)	(76,147,000)
Cash Flows From Financing Activities:
Proceeds from issuance of Common Shares, net of issuance cost		10,000,000	20,000,000
Tax benefits from exercise of stock-based awards	895,000	336,000	107,000
Receipt of advances for and contributions in aid of construction	9,647,000	7,489,000	5,944,000
Refunds on advances for construction	(3,614,000)	(4,136,000)	(3,712,000)
Retirement or repayments of long-term debt	(8,303,000)	(22,380,000)	(371,000)
Proceeds from issuance of long-term debt, net of issuance costs	3,408,000	61,912,000
Net change in inter-company borrowings	(2,000,000)	(33,785,000)	25,400,000
Dividends paid	(10,200,000)	(20,000,000)	(19,600,000)
Other	(389,000)	(237,000)	(181,000)
Net cash provided (used)	(10,556,000)	(801,000)	27,587,000
Net increase (decrease) in cash and cash equivalents	22,578,000	(1,541,000)	445,000
Cash and cash equivalents, beginning of year		1,541,000	1,096,000
Cash and cash equivalents, end of year	22,578,000		1,541,000
Cash and cash equivalents of continuing operations	$ 22,578,000