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v3.19.3.a.u2

Other long-term liabilities - Schedule of Long-Term Liabilities and Deferred Credits (Detail) - USD ($) $ in Thousands | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Oct. 01, 2019 | Jan. 01, 2019 | Dec. 31, 2017
Other Long-term Liabilities |  |  |  |  |
Advances in aid of construction (a) | $ 60,828 | $ 63,703 |  |  |
Environmental remediation obligation (b) | 58,061 | 55,621 |  |  | $ 54,322
Asset retirement obligations (c) | 53,879 | 43,291 |  |  | $ 44,166
Customer deposits (d) | 31,946 | 29,974 |  |  |
Unamortized investment tax credits (e) | 18,234 | 17,491 |  |  |
Deferred credits (f) | 18,952 | 42,711 |  |  |
Preferred shares, Series C (g) | 13,793 | 13,418 |  |  |
Lease liabilities (note 1(q)) | 9,695 |  | $ 1,316 | $ 8,295 |
Lease liabilities (note 1(q)) |  | 3,436 |  |  |
Other (h) | 35,952 | 28,360 |  |  |
Other Liabilities | 301,340 | 298,005 |  |  |
Less: current portion | (57,939) | (42,337) |  |  |
Other long-term liabilities | 243,401 | 255,668 |  |  |
Transfers from advances in aid of construction to contributions in aid of construction | 5,465 | 3,687 |  |  |
Estimated environmental remediation costs | 58,484 | 59,181 |  |  |
Accrual for environmental loss contingencies to be incurred over next four years | $ 36,382 |  |  |  |
Accrual for environmental loss contingencies, payment period | 31 years |  |  |  |
Amount of regulatory assets | $ 559,887 | 460,095 |  |  |
Minimum |  |  |  |  |
Other Long-term Liabilities |  |  |  |  |
Other liability repayment period | 5 years |  |  |  |
Accrual environmental cost | 1.70% |  |  |  |
Maximum |  |  |  |  |
Other Long-term Liabilities |  |  |  |  |
Other liability repayment period | 40 years |  |  |  |
Accrual environmental cost | 2.10% |  |  |  |
Environmental costs |  |  |  |  |
Other Long-term Liabilities |  |  |  |  |
Regulatory asset, expenditure recovery provided by regulator, time period | 7 years |  |  |  |
Amount of regulatory assets | $ 82,300 | $ 82,295 |  |  |
Series C Preferred Stock |  |  |  |  |
Other Long-term Liabilities |  |  |  |  |
Preferred shares, Series C (g) | $ 13,793 |  |  |  |

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