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Share-based Payment Arrangements - Summary of Fair Value using Trinomial Tree Model and Inputs (Detail) | 12 Months Ended
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Dec. 31, 2021 Years ¥ / shares | Dec. 31, 2020 Years yr ¥ / shares | Dec. 31, 2019 yr Years ¥ / shares
Trinomial Tree Model [member] | USISH stock option plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Share price at the grant date |  |  | ¥ 15.84
Exercise price |  |  | 13.34
Trinomial Tree Model [member] | USISH two thousand and twenty share options plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Share price at the grant date |  | ¥ 21.55 |
Exercise price |  | 21.65 |
Binomial Method [Member] | USISH core employees stock ownership plan restricted shares amended in 2020 [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Share price at the grant date |  |  | 16.60
Exercise price |  |  | ¥ 13.34
Expected volatility |  |  | 57.21%
Lock-up periods | Years |  |  | 1
Risk free interest rate |  |  | 1.55%
Binomial Method [Member] | USISH core employees stock ownership plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Share price at the grant date |  |  | ¥ 16.30
Exercise price |  |  | ¥ 13.34
Expected volatility |  |  | 47.77%
Lock-up periods | Years |  |  | 1
Risk free interest rate |  |  | 2.70%
Binomial Method [Member] | USISH employee stock ownership restricted stock ownership plan amendment 2020 [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Share price at the grant date |  | ¥ 24.30 |
Expected volatility |  | 56.97% |
Lock-up periods | Years |  | 1.3 |
Risk free interest rate |  | 2.63% |
Binomial Method [Member] | USISH employee stock ownership restricted stock ownership plan amendment 2021 [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Share price at the grant date | ¥ 14.65 |  |
Expected volatility | 47.15% |  |
Lock-up periods | Years | 1.3 |  |
Risk free interest rate | 2.34% |  |
Bottom of range [member] | Trinomial Tree Model [member] | USISH stock option plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Expected volatility |  |  | 45.07%
Expected lives | yr |  |  | 3
Risk free interest rate |  |  | 2.80%
Bottom of range [member] | Trinomial Tree Model [member] | USISH two thousand and twenty share options plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Expected volatility |  | 48.14% |
Expected lives | yr |  | 2.2 |
Risk free interest rate |  | 2.80% |
Top of range [member] | Trinomial Tree Model [member] | USISH stock option plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Expected volatility |  |  | 51.80%
Expected lives | yr |  |  | 5
Risk free interest rate |  |  | 2.97%
Top of range [member] | Trinomial Tree Model [member] | USISH two thousand and twenty share options plan [Member] |  |  |
Disclosure of terms and conditions of share-based payment arrangement [Line Items] |  |  |
Expected volatility |  | 53.57% |
Expected lives | yr |  | 4.2 |
Risk free interest rate |  | 2.99% |

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- Definition The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2021-01-01 -Paragraph 47 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_47_a_i&doctype=Standard -URIDate 2021-03-24 + Details
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- Definition The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2021-01-01 -Paragraph 47 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_47_a_i&doctype=Standard -URIDate 2021-03-24 + Details
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