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Capital stock - Movement of Ordinary Shares Issued (Detail) - Ordinary shares [member] - shares shares in Thousands |  | 12 Months Ended
--- | --- | ---
Aug. 15, 2018 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of classes of share capital [line items] |  |  |  |
Beginning balance |  | 727,240 | 727,265 | 856,059
Restricted shares – cancelled |  |  | (25) | (349)
Restricted shares – uncancelled |  |  |  | (23)
Capital reduction | 132,945 |  |  | (128,422)
Ending balance |  | 727,240 | 727,240 | 727,265

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- Definition The number of shares issued by the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 106 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d&doctype=Standard -URIDate 2020-01-01 + Details
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