Debt Instrument, Original Issuance Discount

No definition available.

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Namespace Prefix:	gnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of short-term and long-term debt and lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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

- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

+ Details

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

- Definition

Amount of long-term debt and lease obligation, classified as noncurrent.

+ References

+ Details

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

- Definition

Amount of long-term debt and lease obligation, classified as current.

+ References

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=gnc_FILOAssetbasedTermLoanFacilityMember
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Data Type:	na
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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- Details

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- Details

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- Details

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- Details

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- Details

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LONG-TERM DEBT / INTEREST EXPENSE - Schedule of Long-Term Debt (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018	Nov. 30, 2018	Sep. 30, 2018
Debt Instrument
Net carrying amount	$ 858,586,000	$ 1,152,322,000
Unpaid original issuance discount	0	11,445,000		$ 13,231,000
Debt issuance costs	(499,000)	(762,000)
Less: current debt	(152,919,000)	(158,756,000)
Long-term debt	705,667,000	993,566,000
FILO Term Loan \| Term Loan \| FILO Asset-based Term Loan Facility
Debt Instrument
Origination issuance discount (OID)	8,900,000	10,900,000
Net carrying amount	266,132,000	264,086,000
FILO Term Loan \| Revolving Credit Facility
Debt Instrument
Net carrying amount	0
Convertible Senior Notes \| Notes
Debt Instrument
Origination issuance discount (OID)	5,419,000	11,489,000
Net carrying amount	152,944,000	175,504,000
Tranche B-1 \| Term Loan Facility \| Term Loan Facility Due March 2019
Debt Instrument
Net carrying amount	0	147,289,000
Tranche B-2 \| Term Loan Facility \| Amended Term Loan Facility Due March 2021
Debt Instrument
Origination issuance discount (OID)	8,500,000	17,500,000
Net carrying amount	$ 440,009,000	$ 554,760,000	$ 100,000,000