Represents the aggregate cash consideration to acquire investments

No definition available.

Name:	cmcm_AggregateCashConsiderationToAcquireInvestments
Namespace Prefix:	cmcm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of shares which voting rights are delegated to the entity.

+ References

No definition available.

+ Details

Name:	cmcm_BusinessCombinationNumberOfSharesAcquiredThroughDelegation
Namespace Prefix:	cmcm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the number of shares to the total shares which voting rights are delegated to the entity.

+ References

No definition available.

+ Details

Name:	cmcm_BusinessCombinationSharesAcquiredThroughDelegationPercent
Namespace Prefix:	cmcm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents additional percentage of equity interest acquired.

+ References

No definition available.

+ Details

Name:	cmcm_EquityMethodInvestmentAdditionalOwnershipPercentage
Namespace Prefix:	cmcm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents number of third parties.

+ References

No definition available.

+ Details

Name:	cmcm_NumberOfThirdParties
Namespace Prefix:	cmcm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of voting equity interests acquired in a business combination achieved in stages, including equity interests in the acquiree held by the acquirer immediately before the acquisition date and acquired at the acquisition date.

+ References

No definition available.

+ Details

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

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=cmcm_AmericanDepositarySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=cmcm_KingsoftJapanIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SUBSEQUENT EVENTS(Details) - Subsequent Event $ in Thousands, ¥ in Millions				4 Months Ended
	Apr. 22, 2016 CNY (¥)	Jan. 29, 2016 shares	Jan. 19, 2016 JPY (¥) item	Apr. 22, 2016 USD ($)	Apr. 22, 2016 CNY (¥)	Mar. 16, 2016 USD ($)
SUBSEQUENT EVENTS
Aggregate cash consideration				$ 6,541	¥ 42,370,000
ADS
SUBSEQUENT EVENTS
Stock repurchase program, authorized amount \| $						$ 100,000
Stock Repurchased During Period, Value	¥ 0
Kingsoft Japan
SUBSEQUENT EVENTS
Number of third parties for equity transfer agreement \| item			3
Percentage of additional equity interest acquired			4.63%
Cash consideration			¥ 136
Number of shares delegated to the Group \| shares		183,540
Percentage of the number of shares delegated to the Group to total shares		5.00%
Voting rights percentage obtained		51.00%