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Share-based Payment Arrangements - Summary of USISH's outstanding share options balance sheet (Detail) - USISH Option Plans [member] - ¥ / shares | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Share options [Member] |  |
Disclosure of range of exercise prices of outstanding share options [Line Items] |  |
Range of Exercise Price Per Share | ¥ 15.5 | ¥ 15.5
Weighted average remaining contractual life of outstanding share options | 5 years 10 months 24 days | 6 years 10 months 24 days
Stock option plans [Member] |  |
Disclosure of range of exercise prices of outstanding share options [Line Items] |  |
Range of Exercise Price Per Share | ¥ 13.3 |
Weighted average remaining contractual life of outstanding share options | 4 years 10 months 24 days |
Core Employees Stock Ownership Plan [Member] |  |
Disclosure of range of exercise prices of outstanding share options [Line Items] |  |
Range of Exercise Price Per Share | ¥ 13.3 |
Weighted average remaining contractual life of outstanding share options | 4 years 3 months 18 days |

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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
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- Definition The exercise price of outstanding share options. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2019-01-01 -Paragraph 45 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2019-en-r&anchor=para_45_d&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The weighted average remaining contractual life of outstanding share options. [Refer: Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2019-01-01 -Paragraph 45 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2019-en-r&anchor=para_45_d&doctype=Standard -URIDate 2019-03-27 + Details
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