Quarterly Results (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 338,911	$ 329,156	$ 340,602	$ 374,507	$ 379,985	$ 367,824	$ 382,271	$ 357,125	$ 1,383,176	$ 1,487,205	$ 947,729
Gross profit	193,873	183,779	194,994	219,748	225,591	216,397	225,005	207,443	792,394	874,436	534,242
Operating income	93,909	88,127	97,620	116,860	124,361	117,453	123,143	109,226	396,516	474,183	244,959
Net income from continuing operations					130,612	101,930	104,748	91,877	336,705	429,167	217,005
Net loss from discontinued operations					(5,084)	(1,154)	(1,668)	(2,311)	0	(10,217)	0
Net income	$ 80,636	$ 77,489	$ 79,287	$ 99,293	$ 125,528	$ 100,776	$ 103,080	$ 89,566	$ 336,705	$ 418,950	$ 217,005
Diluted net income per common share - continuing operations					$ 0.65	$ 0.52	$ 0.55	$ 0.48	$ 1.65	$ 2.20	$ 1.16
Diluted net loss per common share - discontinued operations					$ (0.03)	$ (0.01)	$ (0.01)	$ (0.01)	$ 0.00	$ (0.05)	$ 0.00
Diluted net income per common share	$ 0.39	$ 0.38	$ 0.40	$ 0.49	$ 0.62	$ 0.51	$ 0.54	$ 0.47	$ 1.65	$ 2.15	$ 1.16