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Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Detail of regulatory assets |  |
Regulatory assets, current | $ 229,559 | $ 248,088
Regulatory assets, non-current | 1,233,062 | 1,202,302
Pension |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 604,556 | 576,188
Retired power plant costs |  |
Detail of regulatory assets |  |
Regulatory assets, current | 25,934 | 27,402
Regulatory assets, non-current | 173,877 | 188,843
Income taxes — allowance for funds used during construction (AFUDC) equity |  |
Detail of regulatory assets |  |
Regulatory assets, current | 5,882 | 3,828
Regulatory assets, non-current | 144,104 | 142,852
Deferred fuel and purchased power — mark-to-market (Note 7) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 42,684 | 52,100
Regulatory assets, non-current | 45,047 | 34,845
Deferred fuel and purchased power |  |
Detail of regulatory assets |  |
Regulatory assets, current | 74,898 | 75,637
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 | 44,267 | 48,305
Income taxes — investment tax credit basis adjustment |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,066 | 1,066
Regulatory assets, non-current | 25,850 | 26,218
Lost fixed cost recovery |  |
Detail of regulatory assets |  |
Regulatory assets, current | 48,484 | 59,844
Regulatory assets, non-current | 0 | 0
Palo Verde VIEs (Note 6) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 19,705 | 19,395
Deferred compensation |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 37,750 | 36,413
Deferred property taxes |  |
Detail of regulatory assets |  |
Regulatory assets, current | 8,569 | 8,569
Regulatory assets, non-current | 71,562 | 74,926
Loss on reacquired debt |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,637 | 1,637
Regulatory assets, non-current | 14,487 | 15,305
Tax expense of Medicare subsidy |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,235 | 1,236
Regulatory assets, non-current | 6,984 | 7,415
TCA balancing account |  |
Detail of regulatory assets |  |
Regulatory assets, current | 6,110 | 1,220
Regulatory assets, non-current | 0 | 0
AG-1 deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 2,654 | 2,654
Regulatory assets, non-current | 7,146 | 8,472
Mead-Phoenix transmission line CIAC |  |
Detail of regulatory assets |  |
Regulatory assets, current | 332 | 332
Regulatory assets, non-current | 10,210 | 10,376
Coal reclamation |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,546 | 1,068
Regulatory assets, non-current | 11,842 | 12,396
SCR deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 9,482 | 353
Other |  |
Detail of regulatory assets |  |
Regulatory assets, current | 451 | 3,418
Regulatory assets, non-current | $ 6,193 | $ 0

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