SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF GNC HOLDINGS, INC. - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net (loss) income before income from equity method investments	$ (33,490)	$ (2,418)	$ 16,058	$ (15,262)	$ 58,839	$ (8,590)	$ 13,341	$ 6,190	$ (35,112)	$ 69,780	$ (150,262)
Loss (gain) on forward contracts for the issuance of convertible preferred stock				16,800	(88,900)				16,787	(88,942)	0
Gain on convertible notes repurchase									(3,214)	0	(10,996)
Other operating activities									(1,675)	(4,945)	4,751
Net cash provided by operating activities									96,520	95,868	220,508
Cash flows from investing activities:
Net cash provided by (used in) investing activities									73,386	(16,467)	(23,762)
Cash flows from financing activities:
Proceeds from the issuance of convertible preferred stock									199,950	100,000	0
Convertible notes repurchase									(24,708)	0	0
Minimum tax withholding requirements									(233)	(296)	(253)
Net cash used in financing activities									(119,256)	(75,768)	(168,106)
Net increase in cash and cash equivalents									49,822	3,223	29,537
Beginning balance, cash and cash equivalents				67,224				64,001	67,224	64,001	34,464
Ending balance, cash and cash equivalents	117,046				67,224				117,046	67,224	64,001
GNC Holdings
Cash flows from operating activities:
Net (loss) income before income from equity method investments									(35,112)	69,780	(150,262)
Deficit in (income) loss of subsidiaries									13,668	14,647	162,874
Interests received from intercompany loan									5,164	0	0
Loss (gain) on forward contracts for the issuance of convertible preferred stock									16,787	(88,942)	0
Gain on convertible notes repurchase									(3,214)	0	(15,041)
Other operating activities									7,969	4,791	2,702
Net cash provided by operating activities									5,262	276	273
Cash flows from investing activities:
Capital contribution to subsidiaries									(148,553)	0	0
Net cash provided by (used in) investing activities									(148,553)	0	0
Cash flows from financing activities:
Proceeds from the issuance of convertible preferred stock									199,950	100,000	0
Proceeds from intercompany receivables									19,679	0	0
Payments on intercompany loan									(51,397)	(100,000)	0
Convertible notes repurchase									(24,708)	0	0
Minimum tax withholding requirements									(233)	(296)	(253)
Net cash used in financing activities									143,291	(296)	(253)
Net increase in cash and cash equivalents									0	(20)	20
Beginning balance, cash and cash equivalents				$ 0				$ 20	0	20	0
Ending balance, cash and cash equivalents	$ 0				$ 0				$ 0	$ 0	$ 20