Note 18 - Income Taxes (Details) - Deferred Tax Assets (Liabilities) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2014	May 31, 2013
Deferred tax liabilities:
Intangibles	$ (260,981)	$ (269,972)
Interest expense	(11,291)	(13,685)
Property and equipment	(2,224)	(4,765)
Transfer pricing	(238)	(2,022)
Prepaids and other	(492)	(309)
Deferred tax assets:
Tax credit carry-forwards	32,632	30,797
Capitalized research	15,122
Net operating loss carry-forwards	6,793	27,532
Compensation expense	3,543	3,002
Inventory	3,351	1,894
Reserves not currently deductible	1,110	1,194
Other	1,526	3,640
	(211,149)	(222,694)
Net deferred tax assets (liabilities)	(215,111)	(225,928)
Deferred Tax Assets Liabilities Including Valuation Allowance [Member]
Deferred tax assets:
Deferred Tax Asset Valuation Allowance	(3,962)	(3,234)
Beginning Balance [Member]
Deferred tax assets:
Deferred Tax Asset Valuation Allowance	3,234	1,888
Change Due To Acquisition [Member]
Deferred tax assets:
Changes in Valuation Allowance		362
Additions [Member]
Deferred tax assets:
Changes in Valuation Allowance	1,111	984
Reductions [Member]
Deferred tax assets:
Changes in Valuation Allowance	(367)
Other Valuation Allowance Adjustments [Member]
Deferred tax assets:
Changes in Valuation Allowance	(16)
Ending Balance [Member]
Deferred tax assets:
Deferred Tax Asset Valuation Allowance	$ 3,962	$ 3,234