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Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Detail of regulatory assets |  |
Current | $ 272,870 | $ 203,207
Non-Current | 1,305,437 | 1,304,073
Pension |  |
Detail of regulatory assets |  |
Current | 0 | 0
Non-Current | 656,092 | 660,223
Income taxes — allowance for funds used during construction ("AFUDC") equity |  |
Detail of regulatory assets |  |
Current | 6,815 | 6,800
Non-Current | 159,005 | 154,974
Retired power plant costs |  |
Detail of regulatory assets |  |
Current | 28,182 | 28,182
Non-Current | 121,259 | 142,503
Deferred fuel and purchased power |  |
Detail of regulatory assets |  |
Current | 162,111 | 70,137
Non-Current | 0 | 0
Ocotillo deferral |  |
Detail of regulatory assets |  |
Current | 0 | 0
Non-Current | 80,359 | 38,144
SCR deferral |  |
Detail of regulatory assets |  |
Current | 0 | 0
Non-Current | 74,576 | 52,644
Deferred property taxes |  |
Detail of regulatory assets |  |
Current | 8,569 | 8,569
Non-Current | 51,769 | 58,196
Lost fixed cost recovery |  |
Detail of regulatory assets |  |
Current | 37,868 | 26,067
Non-Current | 0 | 0
Deferred compensation |  |
Detail of regulatory assets |  |
Current | 0 | 0
Non-Current | 36,481 | 36,464
Four Corners cost deferral |  |
Detail of regulatory assets |  |
Current | 8,077 | 8,077
Non-Current | 26,094 | 32,152
Income taxes — investment tax credit basis adjustment |  |
Detail of regulatory assets |  |
Current | 1,097 | 1,098
Non-Current | 23,850 | 24,981
Palo Verde VIEs (Note 6) |  |
Detail of regulatory assets |  |
Current | 0 | 0
Non-Current | 21,100 | 20,635
Coal reclamation |  |
Detail of regulatory assets |  |
Current | 1,068 | 1,546
Non-Current | 17,266 | 17,688
Loss on reacquired debt |  |
Detail of regulatory assets |  |
Current | 1,637 | 1,637
Non-Current | 10,846 | 12,031
Mead-Phoenix transmission line contributions in aid of construction ("CIAC") |  |
Detail of regulatory assets |  |
Current | 332 | 332
Non-Current | 9,463 | 9,712
Demand side management |  |
Detail of regulatory assets |  |
Current | 0 | 0
Non-Current | 7,259 | 0
Tax expense adjustor mechanism |  |
Detail of regulatory assets |  |
Current | 6,121 | 1,612
Non-Current | 0 | 0
Deferred fuel and purchased power — mark-to-market (Note 7) |  |
Detail of regulatory assets |  |
Current | 0 | 36,887
Non-Current | 5,664 | 33,185
Tax expense of Medicare subsidy |  |
Detail of regulatory assets |  |
Current | 1,238 | 1,235
Non-Current | 3,728 | 4,940
AG-1 deferral |  |
Detail of regulatory assets |  |
Current | 2,787 | 2,787
Non-Current | 626 | 2,716
TCA balancing account |  |
Detail of regulatory assets |  |
Current | 4,490 | 6,324
Non-Current | 0 | 2,885
Other |  |
Detail of regulatory assets |  |
Current | 2,478 | 1,917
Non-Current | $ 0 | $ 0

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