Investment, Ownership Interest

No definition available.

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Namespace Prefix:	gnc_
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Balance Type:	na
Period Type:	duration

- Definition

Number Of Joint Ventures

+ References

No definition available.

+ Details

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Namespace Prefix:	gnc_
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Balance Type:	na
Period Type:	duration

- Definition

Proceeds For Investment In Newly Formed Joint Venture

+ References

No definition available.

+ Details

Name:	gnc_ProceedsForInvestmentInNewlyFormedJointVenture
Namespace Prefix:	gnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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 number of countries in which the entity operates as of balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfCountriesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gnc_JVFrameworkAgreementMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gnc_InternationalVitaminCorporationJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

NATURE OF BUSINESS (Details) $ in Millions	1 Months Ended		3 Months Ended
NATURE OF BUSINESS (Details) $ in Millions	Mar. 31, 2019 USD ($) country	Feb. 28, 2019 USD ($) joint_ventures	Mar. 31, 2019 USD ($) segment country
Schedule of Equity Method Investments [Line Items]
Number of reportable segments \| segment			3
Number of international countries in which franchise stores are located \| country	50		50
Number of joint ventures \| joint_ventures		2
JV Framework
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership (percentage)		35.00%
Manufacturing JV
Schedule of Equity Method Investments [Line Items]
Proceeds for investment in newly formed joint venture \| $	$ 101	$ 101	$ 101
Manufacturing JV \| International Vitamin Corporation
Schedule of Equity Method Investments [Line Items]
Ownership interest (percentage)		43.00%