SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT (Details) - USD ($)	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and equivalents	$ 436,000		$ 4,364,000	$ 75,988,000
Income taxes receivable and other receivables	17,867,000		10,793,000
Total current assets	166,875,000		132,697,000
Other assets	5,068,000		6,750,000
Total Assets	1,470,493,000		1,343,959,000
Liabilities and Capitalization
Notes payable to bank	90,000,000		28,000,000
Income taxes payable	149,000		68,000
Other	177,944,000		123,507,000
Deferred taxes	224,530,000		192,852,000
Other	477,271,000		433,607,000
Common shareholders' equity	494,297,000		465,945,000	506,801,000	$ 492,404,000
Total Capitalization and Liabilities	1,470,493,000		1,343,959,000
Total capitalization	815,278,000		786,845,000
Golden State Water Company [Member]
Assets
Cash and equivalents	209,000		2,501,000
Income taxes receivable and other receivables	21,856,000		11,000,000
Total current assets	112,257,000		89,918,000
Other assets	4,906,000		6,702,000
Total Assets	1,384,178,000		1,271,879,000
Liabilities and Capitalization
Inter-company payable	61,726,000		12,000,000
Other	135,971,000		90,955,000
Deferred taxes	227,798,000		195,658,000
Other	480,456,000		436,294,000
Common shareholders' equity	446,770,000		423,730,000	$ 435,190,000	$ 437,613,000
Total Capitalization and Liabilities	1,384,178,000		1,271,879,000
Total capitalization	767,751,000		744,630,000
AWR
Assets
Cash and equivalents	32,000		836,000
Inter-company loan receivables	76,931,000		12,000,000
Income taxes receivable and other receivables	0		11,000
Total current assets	76,963,000		12,847,000
Investments in subsidiaries	506,584,000		479,397,000
Other assets	6,964,000		5,604,000
Total Assets	590,511,000		497,848,000
Liabilities and Capitalization
Notes payable to bank	90,000,000		28,000,000
Income taxes payable	4,043,000		2,579,000
Inter-company payable	0		474,000
Deferred taxes and other liabilities	517,000		28,000
Other	94,560,000		31,081,000
Deferred taxes	0		734,000
Other	1,654,000		822,000
Income taxes payable and other liabilities	1,654,000		88,000
Common shareholders' equity	494,297,000		465,945,000
Total Capitalization and Liabilities	590,511,000		497,848,000
Total capitalization	494,297,000		465,945,000
Notes Payable, Other Payables [Member] | Notes Receivable | Golden State Water Company [Member]
Assets
Notes Receivable, Related Parties, Current	$ 0
Notes Payable, Other Payables [Member] | Notes Receivable | AWR
Assets
Notes Receivable, Related Parties, Current		$ 0	$ 0