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Business Segments 2 (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Segment Reporting [Abstract] |  |  |
Total utility plant | $ 1,204,992 | $ 1,150,926 | $ 1,060,794
Other assets | 211,742 | 319,567 |
Total Assets | 1,416,734 | 1,470,493 |
AWR Parent |  |  |
Segment Reporting [Abstract] |  |  |
Total utility plant | 0 | 0 | 0
Total Assets | 593,757 | 590,511 |
GSWC |  |  |
Segment Reporting [Abstract] |  |  |
Total utility plant | 1,197,940 | 1,145,311 |
Total Assets | 1,326,823 | 1,384,178 |
Segment Reporting Information [Line Items] |  |  |
Depreciation on transportation equipment | 242 | 259 | 641
American States Utility Services [Member] | American States Utility Services [Member] |  |  |
Segment Reporting [Abstract] |  |  |
Total utility plant | $ 7,052 | $ 5,615 | $ 4,678

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- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of transportation equipment over the assets' useful lives. + References No definition available. + Details
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