Consideration Receivable (Details) ¥ in Thousands, $ in Thousands	1 Months Ended	12 Months Ended
May 31, 2019 CNY (¥)	May 31, 2019 HKD ($)	Dec. 31, 2019 HKD ($)	Dec. 31, 2018 HKD ($)	Dec. 31, 2017 HKD ($)
Consideration Receivable.
Consideration receivable (note 5)			$ 0	$ 165,506
Consideration received	¥ 137,370	$ 165,506	$ 325,413	$ 350,655	$ 131,686
Percentage Of Equity Interest			100.00%

The cash inflow associated with the deconsolidation of a previously consolidated subsidiary or the sale of investment in consolidated subsidiaries (generally greater than 50 percent).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration