Segment Information (Details 2) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net sales by product line
Net sales	$ 895,218	$ 688,431	$ 2,569,968	$ 1,995,870
Weight Management [Member]
Net sales by product line
Net sales	560,100	428,100	1,611,000	1,245,800
Targeted Nutrition [Member]
Net sales by product line
Net sales	205,300	160,400	582,800	458,900
Energy, Sports and Fitness [Member]
Net sales by product line
Net sales	45,700	31,900	124,600	87,800
Outer Nutrition [Member]
Net sales by product line
Net sales	35,400	30,200	109,000	92,200
Literature, Promotional and other [Member]
Net sales by product line
Net sales	$ 48,700	$ 37,800	$ 142,600	$ 111,200