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Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands | Sep. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Detail of regulatory assets |  |
Regulatory assets, current | $ 258,317 | $ 106,875
Regulatory assets, non-current | 1,381,179 | 1,313,428
Pension |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 686,511 | 711,059
Retired power plant costs |  |
Detail of regulatory assets |  |
Regulatory assets, current | 28,647 | 9,913
Regulatory assets, non-current | 194,639 | 117,591
Income taxes — allowance for funds used during construction (AFUDC) equity |  |
Detail of regulatory assets |  |
Regulatory assets, current | 6,202 | 6,305
Regulatory assets, non-current | 170,622 | 152,118
Deferred fuel and purchased power — mark-to-market (Note 6) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 45,463 | 0
Regulatory assets, non-current | 33,115 | 42,963
Deferred fuel and purchased power (b) (d) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 73,966 | 12,465
Regulatory assets, non-current | 0 | 0
Four Corners cost deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 8,077 | 6,689
Regulatory assets, non-current | 50,324 | 56,894
Income taxes — investment tax credit basis adjustment |  |
Detail of regulatory assets |  |
Regulatory assets, current | 2,120 | 2,120
Regulatory assets, non-current | 53,225 | 54,356
Lost fixed cost recovery (b) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 67,500 | 61,307
Regulatory assets, non-current | 0 | 0
Palo Verde VIEs (Note 5) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 19,240 | 18,775
Deferred compensation |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 0
Regulatory assets, non-current | 37,265 | 35,595
Deferred property taxes |  |
Detail of regulatory assets |  |
Regulatory assets, current | 8,569 | 0
Regulatory assets, non-current | 77,408 | 73,200
Loss on reacquired debt |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,637 | 1,637
Regulatory assets, non-current | 15,715 | 16,942
Tax expense of Medicare subsidy |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,503 | 1,513
Regulatory assets, non-current | 9,074 | 10,589
Demand side management (c) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 0 | 3,744
Regulatory assets, non-current | 0 | 0
AG-1 deferral |  |
Detail of regulatory assets |  |
Regulatory assets, current | 2,654 | 0
Regulatory assets, non-current | 9,136 | 5,868
Mead-Phoenix transmission line CIAC |  |
Detail of regulatory assets |  |
Regulatory assets, current | 332 | 332
Regulatory assets, non-current | 10,459 | 10,708
Transmission cost adjustor (b) |  |
Detail of regulatory assets |  |
Regulatory assets, current | 4,345 | 0
Regulatory assets, non-current | 0 | 1,588
Coal reclamation |  |
Detail of regulatory assets |  |
Regulatory assets, current | 1,068 | 418
Regulatory assets, non-current | 14,446 | 5,182
Other |  |
Detail of regulatory assets |  |
Regulatory assets, current | 6,234 | 432
Regulatory assets, non-current | $ 0 | $ 0

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