XML 120 R101.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Commitments and Contingencies - Additional Information (Detail) ¥ in Thousands, $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 CNY (¥) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 CNY (¥) | Dec. 31, 2015 CNY (¥) | Dec. 21, 2017 CNY (¥)
Total rental expense for offices | ¥ 78,303 | $ 12,035 | ¥ 88,694 | ¥ 82,710 |
Total other operating lease expenses | 333,813 | $ 51,306 | ¥ 347,711 | ¥ 222,138 |
Loan facility drawn |  |  |  |  | ¥ 22,000
Beijing Security |  |  |  |  |
Loan facility granted | ¥ 44,000 |  |  |  |

X
- Definition Loan receivable maximum lending. + References No definition available. + Details
Name: | cmcm_LoanReceivableMaximumLending
Namespace Prefix: | cmcm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Expenses for the reporting period incurred under operating leases, excluding rental expenses incurred under operating leases. + References No definition available. + Details
Name: | cmcm_OperatingLeasesExpensesOther
Namespace Prefix: | cmcm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value of the amount outstanding under the credit facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13476-108611 + Details
Name: | us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41499-112717 + Details
Name: | us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=cmcm_BeijingKingsoftInternetSecuritySoftwareCoLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |