Earnings Per Share and Capital Stock 2 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capital stock
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic		$ (175,000)	$ (129,000)
Additional disclosure
Dividend Reinvestment Plan Common Stock Capital Shares Reserved for Future Issuance	1,055,948
Common Shares authorized for issuance but unissued under 401(k) Plan	387,300
Common Shares issued as a result of the exercise of stock options	1,800	30,998	32,142
Cash proceeds from the exercise of stock options	$ 30,000	$ 519,000	$ 546,000
Proceeds from Stock Options Exercised, Distributed to Subsidiaries	0	0	0
Exercise of stock options and other issuance of Common Shares	$ 30,000	$ 519,000	$ 546,000
2000 and 2008 Employee Plans
Additional disclosure
Exercise of stock options and other issuance of Common Shares	42,489	88,772	44,906
AWR
Additional disclosure
Cash proceeds from the exercise of stock options	$ 30,000	$ 519,000	$ 546,000
GSWC
Additional disclosure
Exercise of stock options and other issuance of Common Shares	$ 60,000,000		$ 47,500,000
Common Stock [Member]
Additional disclosure
Exercise of stock options and other issuance of Common Shares	42,000	89,000	77,000
Exercise of stock options and other issuance of Common Shares	$ 30,000	$ 519,000	$ 546,000
Common Stock [Member] | GSWC
Additional disclosure
Exercise of stock options and other issuance of Common Shares	5	0	19
Exercise of stock options and other issuance of Common Shares	$ 60,000,000		$ 47,500,000