REGULATORY REQUIREMENTS (Details) $ in Thousands	Dec. 31, 2021 HKD ($)
Futu Securities (Hong Kong) Limited
Regulatory Requirements, Disclosure [Line Items]
Net Capital/ Eligible Equity	$ 6,666,092
Requirement	1,631,080
Excess	5,035,012
Futu Inc
Regulatory Requirements, Disclosure [Line Items]
Net Capital/ Eligible Equity	149,871
Requirement	22,560
Excess	127,311
Futu Clearing Inc
Regulatory Requirements, Disclosure [Line Items]
Net Capital/ Eligible Equity	3,308,395
Requirement	97,565
Excess	3,210,830
Futu Singapore pte Ltd.
Regulatory Requirements, Disclosure [Line Items]
Net Capital/ Eligible Equity	345,424
Requirement	156,646
Excess	188,778
Futu Insurance Brokers (Hong Kong) Limited
Regulatory Requirements, Disclosure [Line Items]
Net Capital/ Eligible Equity	1,718
Requirement	500
Excess	$ 1,218

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	futu_RegulatoryRequirementsDisclosureLineItems
Namespace Prefix:	futu_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of net capital in excess of minimum required net capital, calculated under Aggregate Indebtedness Standard.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

Name:	srt_ExcessNetCapitalAt1500Percent
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum amount of net capital required to be maintained by broker-dealer subsidiary to engage in security transaction, calculated under Aggregate Indebtedness Standard.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

Name:	srt_MinimumNetCapitalRequiredForBrokerDealerSubsidiary1
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of net capital of broker-dealer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

Name:	srt_NetCapital
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_OwnershipAxis=futu_FutuSecuritiesHongKongLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=futu_FutuIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=futu_FutuClearingIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=futu_FutuSingaporePteLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=futu_FutuInsuranceBrokersHongKongLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: