LEASES - ROU assets for operating and finance leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
ROU assets for operating and finance leases
Operating leases	$ 22,997	$ 31,342
Finance leases	2,781	2,632
Real Estate
ROU assets for operating and finance leases
Operating leases	22,783	30,926
Equipment
ROU assets for operating and finance leases
Operating leases	214	416
Finance leases	$ 2,781	$ 2,632

Amount of lessee's right to use underlying asset under finance lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

Name:	us-gaap_FinanceLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_TypeOfArrangementAxis=mnst_RealEstateLeaseArrangementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=mnst_EquipmentLeaseArrangementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: