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Income Taxes - Summary of Income Tax Rate (Detail) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Income Tax Disclosure [Abstract] |  |  |
Canadian statutory income tax rate |  | 26.50% | 26.50%
Impairment of investments [note 2] |  | 8.60% | 8.20%
Net effect of losses not benefited |  | 8.10% | 0.80%
Tax on repatriation of foreign earnings |  | 4.40% | 1.90%
Foreign exchange re-measurement | [1] | 3.40% | 0.10%
Valuation allowance on deferred tax assets |  | 0.60% | 0.00%
Non-taxable capital losses (gains) | [2] | 0.50% | (2.50%)
Manufacturing and processing profits deduction |  | (0.10%) | (0.40%)
Earnings of equity accounted investees |  | (3.60%) | (1.30%)
Research and development tax credits |  | (3.70%) | (2.40%)
Reserve for uncertain tax positions |  | (4.00%) | (0.50%)
Foreign rate differentials |  | (7.30%) | (3.30%)
Others |  | (0.70%) | (0.50%)
Effective income tax rate |  | 32.70% | 26.60%
[1] | Includes foreign exchange gains reported on U.S. dollar denominated assets for Mexican tax purposes that are not recognized for GAAP purposes and losses related to the re-measurement of financial statement balances of foreign subsidiaries, primarily in Mexico, that are maintained in a currency other than their functional currency.
[2] | During the year ended December 31, 2019, the Company had non-taxable capital gains mainly related to the sale of the FP&C business [note 2].

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