SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed statements of income
Operating expenses	$ 355,814	$ 324,809	$ 325,957
Income from continuing operations before income tax expense	90,093	72,086	54,126
Net Income	54,148	45,859	33,197
Weighted Average Number of Common Shares Outstanding	18,999	18,693	18,585
Basic Earnings Per Common Share (in dollars per share)	$ 2.83	$ 2.44	$ 1.78
Weighted Average Number of Diluted Common Shares Outstanding	19,131	18,837	18,736
Fully Diluted Earnings per Common Share (in dollars per share)	$ 2.82	$ 2.43	$ 1.77
AWR
Condensed statements of income
Operating revenues and other income	64	238
Operating expenses	120	521	1,385
Operating income / (loss)	(56)	(283)	(1,385)
Equity in earnings of subsidiaries	54,212	46,483	34,165
Income from continuing operations before income tax expense	54,156	46,200	32,780
Income tax expense (benefit)	8	341	(417)
Net Income	$ 54,148	$ 45,859	$ 33,197
Weighted Average Number of Common Shares Outstanding	18,999	18,693	18,585
Basic Earnings Per Common Share (in dollars per share)	$ 2.83	$ 2.44	$ 1.78
Weighted Average Number of Diluted Common Shares Outstanding	19,131	18,837	18,736
Fully Diluted Earnings per Common Share (in dollars per share)	$ 2.82	$ 2.43	$ 1.77