LEASES - ROU assets for operating and finance leases (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
ROU assets for operating and finance leases
Operating leases	$ 21,802	$ 22,754
Finance leases	2,289	2,120
Real Estate
ROU assets for operating and finance leases
Operating leases	21,674	22,565
Equipment
ROU assets for operating and finance leases
Operating leases	128	189
Finance leases	$ 2,289	$ 2,120

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: