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Shareholders' equity - Reclassification out of AOCI (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | $ 534 | $ 346 | $ 1,581 | $ 1,457
Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | 28 | 22 | 85 | 521
Amortization of prior service credit and net losses recognized during the period in net periodic benefit cost |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | 5,259 | 3,942 | 15,755 | 11,793
Amortization of prior service credit and net losses recognized during the period in net periodic benefit cost | Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | 4,753 | 3,618 | 14,259 | 10,857
Impact of D&Os of the PUC included in regulatory assets |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | (4,725) | (3,596) | (14,174) | (10,790)
Impact of D&Os of the PUC included in regulatory assets | Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | (4,725) | (3,596) | (14,174) | (10,790)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on derivatives | Forward commitments |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | 0 | 0 | 0 | 454
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on derivatives | Forward commitments | Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |
Reclassifications out of accumulated other comprehensive income/(loss) |  |  |  |
Total reclassifications | $ 0 | $ 0 | $ 0 | $ 454

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