Supplementary Information (Summary of Unaudited Results of Operations) (Details) (USD $) In Thousands, except Per Share data	3 Months Ended																12 Months Ended
	Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2009		Sep. 30, 2009		Jun. 30, 2009		Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Supplementary Information
Net sales	$ 1,102,684		$ 1,034,464		$ 1,061,663		$ 1,052,656		$ 983,308		$ 944,763		$ 965,091		$ 981,991		$ 4,251,467	$ 3,875,153	$ 4,361,479
Operating income	115,499		108,366		121,765		122,751		81,883		99,989		109,817		107,909		468,381	399,598	524,868
Net earnings	$ 62,571		$ 55,831		$ 66,565		$ 64,799		$ 40,078		$ 46,866		$ 54,540		$ 54,816		$ 249,766	$ 196,300	$ 261,088
Basic earnings per share	$ 0.76	[1]	$ 0.66	[1]	$ 0.80	[1]	$ 0.78	[1]	$ 0.48	[1]	$ 0.57	[1]	$ 0.67	[1]	$ 0.67	[1]	$ 2.99	$ 2.39	$ 3.19
Diluted earnings per share	$ 0.74	[1]	$ 0.65	[1]	$ 0.78	[1]	$ 0.76	[1]	$ 0.47	[1]	$ 0.56	[1]	$ 0.65	[1]	$ 0.66	[1]	$ 2.93	$ 2.34	$ 3.12

[1] Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding in each quarter. Therefore, the sum of the quarterly earnings per share does not necessarily equal the full year earnings per share disclosed on the Consolidated Statement of Earnings.