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Regulatory Matters 2 (Details) - USD ($) $ in Thousands | 1 Months Ended | 12 Months Ended
--- | --- | ---
Oct. 31, 2005 | Jul. 31, 2005 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Regulatory matters: |  |  |  |  |
Regulatory Asset Not Accruing Carrying Costs |  |  | $ 56,300 |  |
Water |  |  | 295,258 | $ 306,332 | $ 302,931
Pension Costs and Other Postretirement Benefit Costs |  |  |  |  |
Regulatory matters: |  |  |  |  |
Regulatory Asset Not Accruing Carrying Costs |  |  | 36,200 |  |
General Rate Case Memorandum Accounts [Member] |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  |  |  | (9,500)
WRAM |  |  |  |  |
Regulatory matters: |  |  |  |  |
Regulatory adjustment |  |  | $ 9,400 |  |
Cost of Capital, Proceeding for Water Regions [Member] |  |  |  |  |
Regulatory matters: |  |  |  |  |
Weighted Cost of Capital Percent |  |  | 8.34% |  |
GSWC |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | $ 28,340 | (2,042) |
Water |  |  | 295,258 | 306,332 | $ 302,931
GSWC | Pension Costs and Other Postretirement Benefit Costs |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | (33,124) | (33,019) |
Regulatory Assets |  |  | 36,200 |  |
GSWC | Costs deferred for future recovery on Aerojet case |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | (9,516) | (10,656) |
Recovery period |  | 20 years |  |  |
Increase in Revenue Requirement, Recoverable through Surcharges |  | $ 21,300 |  |  |
GSWC | Costs deferred for future recovery on Aerojet case | Maximum |  |  |  |  |
Regulatory matters: |  |  |  |  |
Recovery period | 20 years |  |  |  |
GSWC | Gain (Loss) on Derivative Instruments [Member] |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | (311) | (2,941) |
GSWC | Flow-through taxes, net |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | 15,300 | 17,700 |
GSWC | General Rate Case Memorandum Accounts [Member] |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | $ (5,054) | (10,522) |
GSWC | General Rate Case Memorandum Accounts [Member] | Minimum |  |  |  |  |
Regulatory matters: |  |  |  |  |
Recovery period |  |  | 12 months |  |
GSWC | General Rate Case Memorandum Accounts [Member] | Maximum |  |  |  |  |
Regulatory matters: |  |  |  |  |
Recovery period |  |  | 36 months |  |
GSWC | WRAM, net of MCBA |  |  |  |  |
Regulatory matters: |  |  |  |  |
Commercial paper, term |  |  | 90 days |  |
Amount billed to customers as surcharges |  |  | $ 21,200 |  |
Under (over) collection |  |  | $ (17,763) | (29,556) |
GSWC | WRAM, net of MCBA | Maximum |  |  |  |  |
Regulatory matters: |  |  |  |  |
Recovery period |  |  | 24 months |  |
GSWC | WRAM |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | $ (3,800) |  |
GSWC | Modified Cost Balancing Account |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | $ (21,600) |  |
GSWC | Cost of Capital, Proceeding for Water Regions [Member] |  |  |  |  |
Regulatory matters: |  |  |  |  |
Weighted Cost of Capital Percent |  |  | 7.91% |  |
Revenue Subject to Refund for TCJA [Member] | GSWC |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | $ 8,293 | 0 |
Various refunds to customers | GSWC |  |  |  |  |
Regulatory matters: |  |  |  |  |
Under (over) collection |  |  | 7,517 | $ 6,070 |
Under Collection in Two Way Pension Balancing Account [Member] | GSWC | Pension Costs and Other Postretirement Benefit Costs |  |  |  |  |
Regulatory matters: |  |  |  |  |
Regulatory adjustment |  |  | (3,034) |  |
Regulatory Assets |  |  | $ 3,000 |  |

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