Business Segments 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Total utility plant	$ 1,150,926	$ 1,060,794	$ 1,003,520
Other assets	319,567	283,165
Total Assets	1,470,493	1,343,959
GSWC
Segment Reporting [Abstract]
Total utility plant	1,145,311	1,056,116
Total Assets	1,384,178	1,271,879
Segment Reporting Information [Line Items]
Depreciation on transportation equipment	259	641	678
AWR Parent
Segment Reporting [Abstract]
Total utility plant	0	0	0
Total Assets	590,511	497,848
American States Utility Services [Member] | American States Utility Services [Member]
Segment Reporting [Abstract]
Total utility plant	$ 5,615	$ 4,678	$ 4,640