Fair value and fair value hierarchy of financial instruments - Additional information (Detail) - HKD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [line items]
Transfer between levels during period	$ 0	$ 0
Financial assets at fair value through profit or loss, category [member] \| Level 3 of fair value hierarchy [member]
Disclosure of detailed information about financial instruments [line items]
Unrealized gain (loss)	216,520,744	$ 321,851,173	$ 22,842,231
Gain from disposal of financial assets	$ 168,063,704

The gains (losses) recognised in profit or loss for assets measured at fair value that are attributable to the change in unrealised gains or losses relating to those assets held at the end of the reporting period. [Refer: At fair value [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2022-03-24
-Paragraph 93
-Subparagraph f
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2022-en-r&anchor=para_93_f&doctype=Standard
-URIDate 2022-03-24

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration