CONSOLIDATED STATEMENTS OF CHANGES IN COMMON SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	GOLDEN STATE WATER COMPANY	Common Shares	Common Shares GOLDEN STATE WATER COMPANY	Earnings Reinvested in the Business	Earnings Reinvested in the Business GOLDEN STATE WATER COMPANY
Balances at Dec. 31, 2009	$ 359,430	$ 331,530	$ 223,066	$ 195,821	$ 136,364	$ 135,709
Balances (in shares) at Dec. 31, 2009			18,532,000	134
Add:
Net income	33,197	25,110			33,197	25,110
Issuance of Common Shares	1,838	20,000	1,838	20,000
Issuance of Common Shares (in shares)	68,025		68,000	8
Exercise of stock options	857		857
Exercise of stock options (in shares)	30,500		31,000
Tax benefit from employee stock-based awards	111	107	111	107
Compensation on stock-based awards	1,434	1,148	1,434	1,148
Dividend equivalent rights on stock-based awards not paid in cash	79	73	79	73
Deduct:
Dividends on Common Shares	19,326	19,600			19,326	19,600
Dividend equivalent rights on stock-based awards	79	73			79	73
Balances at Dec. 31, 2010	377,541	358,295	227,385	217,149	150,156	141,146
Balances (in shares) at Dec. 31, 2010			18,631,000	142
Add:
Net income	45,859	34,822			45,859	34,822
Issuance of Common Shares	1,658	10,000	1,658	10,000
Issuance of Common Shares (in shares)	69,434		69,000	4
Exercise of stock options	2,350		2,350
Exercise of stock options (in shares)	88,713		89,000
Tax benefit from employee stock-based awards	336	336	336	336
Compensation on stock-based awards	1,474	1,353	1,474	1,353
Dividend equivalent rights on stock-based awards not paid in cash	103	98	103	98
Deduct:
Dividends on Common Shares	20,552	20,000			20,552	20,000
Dividend equivalent rights on stock-based awards	103	98			103	98
Balances at Dec. 31, 2011	408,666	384,806	233,306	228,936	175,360	155,870
Balances (in shares) at Dec. 31, 2011			18,789,000	146
Add:
Net income	54,148	39,220			54,148	39,220
Issuance of Common Shares		0
Issuance of Common Shares (in shares)	38,519
Exercise of stock options (in shares)	409,700
Exercise of stock options and other issuance of Common Shares	13,295		13,295
Exercise of stock options and other issuance of Common Shares (in shares)			448,000
Tax benefit from employee stock-based awards	890	895	890	895
Compensation on stock-based awards	1,710	1,536	1,710	1,536
Dividend equivalent rights on stock-based awards not paid in cash	121	113	121	113
Deduct:
Dividends on Common Shares	24,130	10,200			24,130	10,200
Dividend equivalent rights on stock-based awards	121	113			121	113
Balances at Dec. 31, 2012	$ 454,579	$ 416,257	$ 249,322	$ 231,480	$ 205,257	$ 184,777
Balances (in shares) at Dec. 31, 2012			19,237,000	146