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Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands |  |  |  | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Oct. 26, 2020 | Oct. 25, 2019 | Oct. 29, 2018 | Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Nov. 21, 2018
Retained Earnings Adjustments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend declared |  |  |  | $ 0.0875 | $ 0.0875 | $ 0.0875 | $ 0.0875 | $ 0.0875 | $ 0.075 | $ 0.075 | $ 0.075 | $ 0.075 | $ 0.075 | $ 0.075 | $ 0.075 | $ 0.35 | $ 0.35 | $ 0.30 |
Annual Dividend [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retained Earnings Adjustments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend declared | $ 1.40 | $ 1.40 | $ 1.20 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Quarterly Dividend [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retained Earnings Adjustments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend declared | $ 0.35 | $ 0.35 | $ 0.30 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
American Depositary Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retained Earnings Adjustments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
ADSs repurchased during period, shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 626 | 762 | 1,006 |
ADSs repurchased during period, cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 25,044 | $ 25,103 | $ 34,755 |
Average purchase price per ADS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 39.93 | $ 32.82 | $ 34.54 |
American Depositary Shares | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retained Earnings Adjustments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repurchase of shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 200,000

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