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Share-based Payment Arrangements - Summary of Outstanding Restricted Shares At Balance Sheet (Detail) - USISH option plans [member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
2019 restricted shares [Member]
Dislcosure of Range Exercise Prices of Outstanding Restricted Shares [Line Items]
Range of Exercise Price Per Share	13.2	13.3
Remaining Contractual Life (Years)	3 years 3 months 18 days	4 years 3 months 18 days
2020 restricted shares [Member]
Dislcosure of Range Exercise Prices of Outstanding Restricted Shares [Line Items]
Remaining Contractual Life (Years)	1 year 8 months 12 days

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Dislcosure of Range Exercise Prices of Outstanding Restricted Shares [Line Items].

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Exercise Price of Outstanding Restricted Shares 2019.

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Weighted Average Remaining Contractual Life of Outstanding Restricted Shares 2019.

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