Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 item	Mar. 31, 2013
Segment Information
Number of business segments			4
Segment Information
Net sales	$ 779,026	$ 757,874	$ 1,606,131	$ 1,547,101
Income (loss) from operations	50,268	23,490	164,450	128,615
Depreciation and amortization	25,834	29,279	51,399	52,670
Capital expenditures	25,997	30,174	47,244	63,692
Reportable Business Segments
Segment Information
Net sales	779,026	757,874	1,606,131	1,547,101
Income (loss) from operations	78,009	87,422	214,464	215,464
Depreciation and amortization	16,814	16,952	33,462	33,458
Capital expenditures	13,789	7,189	23,343	16,341
Corporate/Manufacturing
Segment Information
Income (loss) from operations	(27,741)	(63,932)	(50,014)	(86,849)
Depreciation and amortization	9,020	12,327	17,937	19,212
Capital expenditures	12,208	22,985	23,901	47,351
Wholesale | Reportable Business Segments
Segment Information
Net sales	443,449	445,672	948,723	939,876
Income (loss) from operations	19,004	26,964	101,732	96,891
Depreciation and amortization	9,081	10,068	18,167	19,697
Capital expenditures	172	55	203	230
European Retail | Reportable Business Segments
Segment Information
Net sales	215,317	187,103	420,229	366,087
Income (loss) from operations	49,915	42,517	93,875	82,501
Depreciation and amortization	4,133	3,766	8,177	7,509
Capital expenditures	9,547	5,810	14,868	13,918
European Retail | Reportable Business Segments | Holland & Barrett
Segment Information
Number of stores	743		743
European Retail | Reportable Business Segments | Holland & Barrett | China
Segment Information
Number of franchised stores	27		27
European Retail | Reportable Business Segments | Holland & Barrett | Singapore
Segment Information
Number of franchised stores	27		27
European Retail | Reportable Business Segments | Holland & Barrett | United Arab Emirates
Segment Information
Number of franchised stores	8		8
European Retail | Reportable Business Segments | Holland & Barrett | Cyprus
Segment Information
Number of franchised stores	8		8
European Retail | Reportable Business Segments | Holland & Barrett | Malta
Segment Information
Number of franchised stores	4		4
European Retail | Reportable Business Segments | Holland & Barrett | Gibraltar
Segment Information
Number of franchised stores	1		1
European Retail | Reportable Business Segments | Holland & Barrett | Iceland
Segment Information
Number of franchised stores	1		1
European Retail | Reportable Business Segments | De Tuinen | Netherlands
Segment Information
Number of stores	131		131
Number of franchised stores	7		7
European Retail | Reportable Business Segments | GNC (UK) stores | U.K.
Segment Information
Number of stores	57		57
European Retail | Reportable Business Segments | GNC (UK) stores | Ireland
Segment Information
Number of stores	47		47
European Retail | Reportable Business Segments | GNC (UK) stores | Belgium
Segment Information
Number of stores	13		13
Direct Response/E-Commerce | Reportable Business Segments
Segment Information
Net sales	63,601	63,898	123,963	122,582
Income (loss) from operations	7,388	11,075	14,363	23,324
Depreciation and amortization	2,833	2,505	5,645	5,009
Capital expenditures	113	656	682	768
North American Retail | Reportable Business Segments
Segment Information
Net sales	56,659	61,201	113,216	118,556
Income (loss) from operations	1,702	6,866	4,494	12,748
Depreciation and amortization	767	613	1,473	1,243
Capital expenditures	$ 3,957	$ 668	$ 7,590	$ 1,425
North American Retail | Reportable Business Segments | Vitamin World
Segment Information
Number of stores	417		417