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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.

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Revenue earned during the period from periodic fees charged to existing members of an association or club. An example would be the monthly/annual dues paid to a gym or workout facility. This element excludes the initial membership fees received on enrollment or registration.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
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The amount of revenue recognized for the period under subleasing arrangements.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 55
-Paragraph 3
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Amount, after sales adjustments, returns, allowances, and discounts, of revenue classified as other.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Revenue earned during the period from franchisor owned outlets.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 952
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-Section 45
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Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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SEGMENTS - U.S. and Canada Sales by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer
Revenue	$ 557,737	$ 609,469	$ 640,994	$ 644,838	$ 569,929	$ 627,964	$ 673,218	$ 668,905	$ 2,453,038	$ 2,540,016	$ 2,683,298
U.S. and Canada
Revenue from External Customer
Total U.S. company-owned product sales									1,541,586	1,559,706	1,656,862
Wholesale sales to franchisees									242,521	250,779	257,497
Royalties and franchise fees									33,149	34,469	35,350
Sublease income									48,972	47,555	44,086
Gold Card revenue recognized in U.S.(1)									24,399	62,211	59,247
Other									102,817	103,291	114,963
Revenue									1,993,444	2,058,011	2,168,005
U.S. and Canada \| Protein
Revenue from External Customer
Total U.S. company-owned product sales									338,773	369,150	389,917
U.S. and Canada \| Performance supplements
Revenue from External Customer
Total U.S. company-owned product sales									281,532	254,753	246,662
U.S. and Canada \| Weight management
Revenue from External Customer
Total U.S. company-owned product sales									140,148	154,195	165,114
U.S. and Canada \| Vitamins
Revenue from External Customer
Total U.S. company-owned product sales									203,569	218,908	271,099
U.S. and Canada \| Herbs / Greens
Revenue from External Customer
Total U.S. company-owned product sales									66,324	63,356	70,924
U.S. and Canada \| Wellness
Revenue from External Customer
Total U.S. company-owned product sales									196,942	200,914	211,377
U.S. and Canada \| Health / Beauty
Revenue from External Customer
Total U.S. company-owned product sales									190,977	164,510	149,520
U.S. and Canada \| Food / Drink
Revenue from External Customer
Total U.S. company-owned product sales									94,390	105,134	124,865
U.S. and Canada \| General merchandise
Revenue from External Customer
Total U.S. company-owned product sales									$ 28,931	$ 28,786	$ 27,384