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

No definition available.

+ Details

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

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121559654&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

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

- Details

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

- Details

Name:	srt_OwnershipAxis=futu_FutuNetworkTechnologyShenzhenCo.LtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=futu_ShenSiNetworkTechnologyBeijingCo.LtdMember
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_ShenzhenFutuNetworkTechnologyCo.LtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=futu_BeijingFutuNetworkTechnologyCo.LtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=futu_LeafHuaLiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=futu_LeiLiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

GENERAL INFORMATION, ORGANIZATION AND PRINCIPAL ACTIVITIES (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 18, 2007
"Futu Securities" or the "Operating Company"
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, Subsidiaries	100.00%
Futu Securities (Hong Kong) Limited
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, Subsidiaries	100.00%
Futu Network Technology Limited
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, Subsidiaries	100.00%
Futu Network Technology (Shenzhen) Co., Ltd
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, Subsidiaries	100.00%
Shen Si
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, Subsidiaries	100.00%
Futu Inc
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, Subsidiaries	100.00%
Shenzhen Futu
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, VIE's and Subsidiaries of VIE's	100.00%
Beijing Futu Network Technology Co., Ltd
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of Direct or Indirect Economic Interest, VIE's and Subsidiaries of VIE's	100.00%
Mr. Leaf Hua Li \| Shenzhen Futu
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of equity interest (as a percent)		85.00%
Ms. Lei Li \| Shenzhen Futu
ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of equity interest (as a percent)		15.00%