SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF GNC HOLDINGS, INC. - Statements of Income and Comprehensive Income (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Condensed Financial Statements
Operating (loss) income	$ (394,231)	$ 40,445	$ 39,820	$ 53,553	$ (448,129)	$ 64,893	$ 116,224	$ 94,065	$ (260,413)	$ (172,947)	$ 393,107
Interest expense, net									64,221	60,443	50,936
Gain on convertible debt and debt refinancing costs (Note 7)									(10,996)	0	0
(Loss) income before income taxes									(313,638)	(233,390)	342,171
Income tax benefit									(164,787)	52,860	122,872
Net (loss) income	$ (209,825)	$ 21,463	$ 15,661	$ 23,850	$ (433,447)	$ 32,354	$ 64,028	$ 50,815	(148,851)	(286,250)	219,299
Other comprehensive (loss) income:
Foreign currency translation gain (loss)									2,866	952	(7,439)
Release of cumulative translation loss to earnings related to substantial liquidation of Discount Supplements									0	0	1,619
Other comprehensive income (loss)									2,866	952	(5,820)
Comprehensive (loss) income									$ (145,985)	$ (285,298)	$ 213,479
(Loss) Earnings per share:
Basic (in USD per share)	$ (2.99)	$ 0.31	$ 0.23	$ 0.35	$ (6.35)	$ 0.47	$ 0.94	$ 0.70	$ (2.16)	$ (4.12)	$ 2.61
Diluted (in USD per share)	$ (2.99)	$ 0.31	$ 0.23	$ 0.35	$ (6.35)	$ 0.47	$ 0.94	$ 0.69	$ (2.16)	$ (4.12)	$ 2.60
Weighted average common shares outstanding:
Basic (in shares)	70,251	68,354	68,287	68,246	68,219	68,190	68,176	73,078	68,789	69,409	83,927
Diluted (in shares)	70,251	68,569	68,362	68,300	68,219	68,315	68,303	73,373	68,789	69,409	84,186
Common stock dividends (in USD per share)									$ 0	$ 0.80	$ 0.72
GNC Holdings
Condensed Financial Statements
Selling, general and administrative									$ 1,238	$ 1,543	$ 1,645
Subsidiary loss (income)									161,463	279,192	(223,090)
Operating (loss) income									(162,701)	(280,735)	221,445
Interest expense, net									10,399	9,643	4,241
Gain on convertible debt and debt refinancing costs (Note 7)									(15,041)	0	0
(Loss) income before income taxes									(158,059)	(290,378)	217,204
Income tax benefit									(9,208)	(4,128)	(2,095)
Net (loss) income									(148,851)	(286,250)	219,299
Other comprehensive (loss) income:
Foreign currency translation gain (loss)									2,866	952	(7,439)
Release of cumulative translation loss to earnings related to substantial liquidation of Discount Supplements									0	0	1,619
Other comprehensive income (loss)									2,866	952	(5,820)
Comprehensive (loss) income									$ (145,985)	$ (285,298)	$ 213,479
(Loss) Earnings per share:
Basic (in USD per share)									$ (2.16)	$ (4.12)	$ 2.61
Diluted (in USD per share)									$ (2.16)	$ (4.12)	$ 2.60
Weighted average common shares outstanding:
Basic (in shares)									68,789	69,409	83,927
Diluted (in shares)									68,789	69,409	84,186
Common stock dividends (in USD per share)									$ 0.00	$ 0.80	$ 0.72