Segment Information (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales	$ 796,867	$ 815,610	$ 787,876	$ 852,771	$ 792,686	$ 806,961	$ 779,026	$ 827,105	$ 3,226,124	$ 3,205,778	$ 3,163,041
Consolidated long-lived assets	605,708				597,202				605,708	597,202
Consolidated assets	4,854,479				4,809,479				4,854,479	4,809,479
United States
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									1,934,729	1,934,668	2,024,178
Consolidated long-lived assets	387,376				399,296				387,376	399,296
U.K.
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									812,685	767,173	675,378
Consolidated long-lived assets	160,131				146,814				160,131	146,814
Canada
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									116,296	118,814	129,476
Consolidated long-lived assets	6,419				10,687				6,419	10,687
Netherlands
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									112,205	116,107	98,673
Consolidated long-lived assets	22,969				15,778				22,969	15,778
Ireland
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									35,820	40,235	36,655
Consolidated long-lived assets	8,937				4,454				8,937	4,454
Other foreign countries
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									214,389	228,781	198,681
Consolidated long-lived assets	19,876				20,173				19,876	20,173
Adjustment
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets	(13,930)								(13,930)
Operating segments
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									3,226,124	3,205,778	3,163,041
Consolidated assets	4,040,513				4,061,662				4,040,513	4,061,662
Corporate/Manufacturing
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets	813,966				747,817				813,966	747,817
Corporate/Manufacturing | Adjustment
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets					2,520					2,520
Consumer Products Group | Operating segments
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									1,883,164	1,879,481	1,938,921
Consolidated assets	2,535,813				2,497,273				2,535,813	2,497,273
Consumer Products Group | Operating segments | Adjustment
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets	(7,129)				(3,386)				(7,129)	(3,386)
Holland & Barrett International | Operating segments
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									885,872	850,797	743,861
Consolidated assets	941,739				944,924				941,739	944,924
Holland & Barrett International | Operating segments | Adjustment
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets	(3,086)				(3,086)				(3,086)	(3,086)
Puritan's Pride | Operating segments
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									248,982	250,224	246,731
Consolidated assets	511,080				509,503				511,080	509,503
Puritan's Pride | Operating segments | Adjustment
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets	(3,715)				(3,139)				(3,715)	(3,139)
Vitamin World | Operating segments
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated net sales									208,106	225,276	$ 233,528
Consolidated assets	$ 51,881				109,962				$ 51,881	109,962
Vitamin World | Operating segments | Adjustment
Total net sales by location of customer and long-lived assets-property, plant and equipment
Consolidated assets					$ (2,552)					$ (2,552)