CONSOLIDATED STATEMENTS OF INCOME (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Revenues
Water	$ 305,898,000	$ 300,450,000	$ 291,617,000
Electric	37,033,000	36,275,000	35,799,000
Contracted services	123,977,000	83,188,000	72,360,000
Total operating revenues	466,908,000	419,913,000	399,776,000
Operating Expenses
Water purchased	54,010,000	47,530,000	46,865,000
Power purchased for pumping	8,355,000	8,598,000	9,113,000
Groundwater production assessment	14,732,000	13,550,000	11,473,000
Power purchased for resale	12,120,000	13,574,000	13,078,000
Supply cost balancing accounts	11,709,000	18,748,000	20,622,000
Other operation expenses	29,790,000	28,312,000	29,107,000
Administrative and general expenses	70,556,000	74,061,000	86,266,000
Depreciation and amortization	41,385,000	38,349,000	37,405,000
Maintenance	15,887,000	17,357,000	18,149,000
Property and other taxes	15,381,000	14,210,000	14,165,000
ASUS construction expenses	81,957,000	50,648,000	40,357,000
Net gain on sale of property	(68,000)	(128,000)	(643,000)
Total operating expenses	355,814,000	324,809,000	325,957,000
Operating Income	111,094,000	95,104,000	73,819,000
Other Income and Expenses
Interest expense	(22,765,000)	(23,681,000)	(21,636,000)
Interest income	1,333,000	859,000	2,406,000
Other	431,000	(196,000)	(463,000)
Total other income and expenses	(21,001,000)	(23,018,000)	(19,693,000)
Income from continuing operations before income tax expense	90,093,000	72,086,000	54,126,000
Income tax expense	35,945,000	30,076,000	23,035,000
Income from continuing operations	54,148,000	42,010,000	31,091,000
Income from discontinued operations, net of tax		3,849,000	2,106,000
Net Income	54,148,000	45,859,000	33,197,000
Basic Earnings Per Common Share
Income from continuing operations (in dollars per share)	$ 2.83	$ 2.24	$ 1.67
Income from discontinued operations, net of tax (in dollars per share)		$ 0.20	$ 0.11
Net Income (in dollars per share)	$ 2.83	$ 2.44	$ 1.78
Fully Diluted Earnings Per Share
Income from continuing operations (in dollars per share)	$ 2.82	$ 2.23	$ 1.66
Income from discontinued operations, net of tax (in dollars per share)		$ 0.20	$ 0.11
Net Income (in dollars per share)	$ 2.82	$ 2.43	$ 1.77
Weighted Average Number of Shares Outstanding (in shares)	18,999	18,693	18,585
Weighted Average Number of Diluted Shares (in shares)	19,131	18,837	18,736
Dividends Declared Per Common Share (in dollars per share)	$ 1.27	$ 1.10	$ 1.04
GOLDEN STATE WATER COMPANY
Operating Revenues
Water	305,898,000	300,450,000	291,617,000
Electric	37,033,000	36,275,000	35,799,000
Total operating revenues	342,931,000	336,725,000	327,416,000
Operating Expenses
Water purchased	54,010,000	47,530,000	46,865,000
Power purchased for pumping	8,355,000	8,598,000	9,113,000
Groundwater production assessment	14,732,000	13,550,000	11,473,000
Power purchased for resale	12,120,000	13,574,000	13,078,000
Supply cost balancing accounts	11,709,000	18,748,000	20,622,000
Other operation expenses	26,938,000	24,579,000	25,424,000
Administrative and general expenses	60,139,000	61,582,000	72,582,000
Depreciation and amortization	40,197,000	37,461,000	36,600,000
Maintenance	14,356,000	14,702,000	15,840,000
Property and other taxes	13,835,000	12,851,000	12,658,000
Net gain on sale of property	(65,000)	(128,000)	(640,000)
Total operating expenses	256,326,000	253,047,000	263,615,000
Operating Income	86,605,000	83,678,000	63,801,000
Other Income and Expenses
Interest expense	(22,609,000)	(23,292,000)	(21,215,000)
Interest income	1,293,000	801,000	1,914,000
Other	431,000	(394,000)	(307,000)
Total other income and expenses	(20,885,000)	(22,885,000)	(19,608,000)
Income from continuing operations before income tax expense	65,720,000	60,793,000	44,193,000
Income tax expense	26,500,000	25,971,000	19,083,000
Net Income	$ 39,220,000	$ 34,822,000	$ 25,110,000