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Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
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Detail of regulatory assets |  |
Regulatory assets, current | $ 135,225 | $ 166,902
Regulatory assets, non-current | 1,321,507 | 1,342,941
Pension |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 723,307 | 733,351
Retired power plant costs |  |
Detail of regulatory assets |  |
Regulatory assets, current | 28,182 | 28,182
Regulatory assets, non-current | 160,167 | 167,164
Income taxes — allowance for funds used during construction (AFUDC) equity |  |
Detail of regulatory assets |  |
Regulatory assets, current | 6,457 | 6,457
Regulatory assets, non-current | 151,541 | 151,467
Deferred fuel and purchased power — mark-to-market (Note 7) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 29,340 | 31,728
Regulatory assets, non-current | 14,360 | 23,768
Deferred fuel and purchased power |  |
Detail of regulatory assets |  |
Regulatory assets, current | 7,583 | 37,164
Regulatory assets, non-current | 0 | 0
Four Corners cost deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 8,077 | 8,077
Regulatory assets, non-current | 38,209 | 40,228
Income taxes — investment tax credit basis adjustment |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,079 | 1,079
Regulatory assets, non-current | 25,475 | 25,522
Lost fixed cost recovery |  |
Detail of regulatory assets |  |
Regulatory assets, current | 29,698 | 32,435
Regulatory assets, non-current | 0 | 0
Palo Verde VIEs (Note 6) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 20,170 | 20,015
Deferred compensation |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 37,581 | 36,523
Deferred property taxes |  |
Detail of regulatory assets |  |
Regulatory assets, current | 8,569 | 8,569
Regulatory assets, non-current | 64,214 | 66,356
Loss on reacquired debt |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,637 | 1,637
Regulatory assets, non-current | 13,259 | 13,668
Tax expense of Medicare subsidy |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,235 | 1,235
Regulatory assets, non-current | 6,122 | 6,176
TCA balancing account |  |
Detail of regulatory assets |  |
Regulatory assets, current | 306 | 3,860
Regulatory assets, non-current | 0 | 772
AG-1 deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 2,654 | 2,654
Regulatory assets, non-current | 5,155 | 5,819
Mead-Phoenix transmission line CIAC |  |
Detail of regulatory assets |  |
Regulatory assets, current | 332 | 332
Regulatory assets, non-current | 9,961 | 10,044
Coal reclamation |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,546 | 1,546
Regulatory assets, non-current | 17,392 | 15,607
SCR deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 30,581 | 23,276
Tax expense adjustor mechanism |  |
Detail of regulatory assets |  |
Regulatory assets, current | 5,451 | 0
Regulatory assets, non-current | 0 | 0
Other |  |
Detail of regulatory assets |  |
Regulatory assets, current | 3,079 | 1,947
Regulatory assets, non-current | $ 4,013 | $ 3,185

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