Litigation Settlement, Settlement Agreement, Term of Agreement

No definition available.

Name:	gnc_LitigationSettlementSettlementAgreementTermofAgreement
Namespace Prefix:	gnc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss Contingency, Number of Unused Patents

+ References

No definition available.

+ Details

Name:	gnc_LossContingencyNumberofUnusedPatents
Namespace Prefix:	gnc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Loss Contingency, Period of Unused Patents

+ References

No definition available.

+ Details

Name:	gnc_LossContingencyPeriodofUnusedPatents
Namespace Prefix:	gnc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of aggregate cap on retained loss for deductible/retention per claim out of total product liability insurance.

+ References

No definition available.

+ Details

Name:	gnc_ProductLiabilityContingencyInsuranceAggregateCapOnRetainedLoss
Namespace Prefix:	gnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of deductible/retention per claim out of total product liability insurance.

+ References

No definition available.

+ Details

Name:	gnc_ProductLiabilityContingencyInsuranceDeductibleOrRetentionPerClaim
Namespace Prefix:	gnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

+ Details

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

- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Definition

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

+ References

+ Details

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

- Definition

The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates.

+ References

+ Details

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

- Definition

The total number of new claims filed pertaining to a loss contingency during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

+ Details

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

- Definition

Number of pending claims pertaining to a loss contingency.

+ References

+ Details

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

- Details

Name:	us-gaap_LitigationCaseAxis=gnc_HollandandBarrettLicenseLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gnc_PennsylvaniaFluctuatingWorkweekJasonOliveVersusGeneralNutritionCorporationAndGovernmentRegulationMatterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gnc_ElizabethNaranjoCaliforniaWageandBreakClaimsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gnc_SubpoenaFromDepartmentofJusticeRelatedtoUSPLabsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_DamagesFromProductDefectsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gnc_DMAAClaimsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

COMMITMENTS AND CONTINGENCIES - Narrative (Details)			1 Months Ended	3 Months Ended	12 Months Ended
COMMITMENTS AND CONTINGENCIES - Narrative (Details)	Sep. 18, 2014 patent	Feb. 29, 2012 action	Dec. 31, 2016	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2015 lawsuit
Commitments and contingencies
Liability related to environmental loss contingency recorded					$ 0
Amount of future purchase commitments					22,800,000
Holland and Barrett License Litigation [Member]
Commitments and contingencies
Legal related charges					4,400,000
Loss contingency, number of unused patents \| patent	5
Loss contingency, period of unused patents	5 years
Loss contingency accrual, provision				$ 2,100,000
Pennsylvania Fluctuating Workweek, Jason Olive Versus General Nutrition Corporation And Government Regulation Matter
Commitments and contingencies
Legal related charges					5,100,000
Elizabeth Naranjo, California Wage and Break Claims
Commitments and contingencies
Number of claims filed against the company \| action		8
Subpoena From Department of Justice Related to USP Labs
Commitments and contingencies
Term of settlement agreement			60 months
Product liability claims
Commitments and contingencies
Deductible/retention per claim					4,000,000
Aggregate cap on retained loss					$ 10,000,000
Product liability claims \| DMAA Claims
Commitments and contingencies
Number of pending lawsuits in which company is named \| lawsuit						32