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Long-Term Debt (Details) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 USD ($) | Dec. 31, 2016 | Dec. 31, 2014 USD ($)
GSWC |  |  |
Long-term debt |  |  |
Ratio of Indebtedness to Net Capital | 0.4332 |  |
Ratio of Indebtedness to EBITDA | 2.5 |  |
GSWC | Maximum |  |  |
Long-term debt |  |  |
Ratio of Indebtedness to Net Capital | 0.6667 |  |
Ratio of Indebtedness to EBITDA | 8 |  |
Private Placement Notes [Member] | GSWC |  |  |
Long-term debt |  |  |
Interest coverage ratio | 400.00% |  |
Private Placement Notes [Member] | GSWC | Minimum |  |  |
Long-term debt |  |  |
Interest coverage ratio | 200.00% |  |
Private placement notes |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 9.56% | 9.56% |
Private placement notes | GSWC |  |  |
Long-term debt |  |  |
Debt Instrument, Face Amount | $ 28,000,000 |  |
Interest rate (as a percent) | 9.56% | 9.56% |
Debt Instrument Redemption Premium above Treasury Yield | 5500.00% |  |
Private placement notes | GSWC | Maximum |  |  |
Long-term debt |  |  |
Redemption premium after 2021 (as a percent) | 3.00% |  |
Private placement notes | American States Utility Services [Member] |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 9.56% |  |
Notes Payable 5.87 Percent Due 2028 [Member] |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 5.87% | 5.87% |
Notes Payable 5.87 Percent Due 2028 [Member] | GSWC |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 5.87% | 5.87% |
Notes Payable 5.87 Percent Due 2028 [Member] | American States Utility Services [Member] |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 5.87% |  |
Notes Payable 6.7 Percent Due 2019 [Member] |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 6.70% | 6.70% |
Notes Payable 6.7 Percent Due 2019 [Member] | GSWC |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 6.70% | 6.70% |
Notes Payable 6.7 Percent Due 2019 [Member] | American States Utility Services [Member] |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 6.70% |  |
Senior Notes issued to Co-Bank | GSWC |  |  |
Long-term debt |  |  |
Additional spread on premium (as a percent) | 0.50% |  |
American Recovery and Reinvestment Act Obligation due 2033 | GSWC |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 2.50% |  |
Notes Payable 3.45 Percent Due 2029 [Member] |  |  |
Long-term debt |  |  |
Interest rate (as a percent) | 3.45% | 3.45% |
Notes Payable 3.45 Percent Due 2029 [Member] | GSWC |  |  |
Long-term debt |  |  |
Debt Instrument, Face Amount | $ 15,000,000 |  | $ 15,000,000
Interest rate (as a percent) | 3.45% | 3.45% | 3.45%

X
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