Consolidated Statements of Income (USD $) In Thousands, except Per Share data	12 Months Ended
	May 31, 2011	May 31, 2010	May 31, 2009
NET SALES	$ 333,091	$ 329,073	$ 300,547	[1]
COST OF SALES (exclusive of amortization shown separately below)	96,175	95,349	84,536	[1]
GROSS MARGIN	236,916	233,724	216,011	[1]
OPERATING EXPENSES
Research and development	15,900	15,437	10,698	[1]
Selling and marketing	36,431	36,995	38,315	[1]
Distribution	16,508	14,831	13,708	[1]
General and administrative	37,747	36,841	32,593	[1]
Amortization expense	4,333	4,278	3,739	[1]
Total operating expenses	110,919	108,382	99,053	[1]
INCOME FROM OPERATIONS	125,997	125,342	116,958	[1]
NON-OPERATING INCOME (EXPENSE)
Interest income	706	454	1,957	[1]
Interest expense	(70)	(33)	(250)	[1]
Other, net	3,997	(551)	(1,684)	[1]
Total non-operating income (expense)	4,633	(130)	23	[1]
INCOME BEFORE INCOME TAXES	130,630	125,212	116,981	[1]
PROVISION FOR INCOME TAXES	41,303	42,629	40,798	[1]
NET INCOME	$ 89,327	$ 82,583	$ 76,183	[1]
Earnings per share:
Per common share - basic (in Dollars per share)	$ 1.27	$ 1.18	$ 1.08	[1]
Per common share - diluted (in Dollars per share)	$ 1.26	$ 1.17	$ 1.07	[1]

[1] Certain numbers have been reclassed to conform to current year presentation.