Goodwill and Intangible Assets - Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended				3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended
	May 31, 2013	Aug. 31, 2014	May 31, 2014	May 31, 2012	Aug. 31, 2014 Product Technologies [Member]	May 31, 2013 Product Technologies [Member]	May 31, 2014 Product Technologies [Member]	Aug. 31, 2014 Customer Relationships [Member]	May 31, 2013 Customer Relationships [Member]	May 31, 2014 Customer Relationships [Member]	Aug. 31, 2014 Licenses [Member]	May 31, 2013 Licenses [Member]	May 31, 2014 Licenses [Member]	Aug. 31, 2014 Trademarks [Member]	May 31, 2013 Trademarks [Member]	May 31, 2014 Trademarks [Member]	Aug. 31, 2014 Distributor Relationships [Member]	May 31, 2014 Distributor Relationships [Member]	Aug. 31, 2014 Trademark-NAMIC [Member]	May 31, 2014 Trademark-NAMIC [Member]	Aug. 31, 2014 In-process Research and Development [Member]	May 31, 2014 In-process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying value, finite intangible items					$ 150,334		$ 150,298	$ 86,579		$ 86,645	$ 7,890		$ 7,639	$ 6,345		$ 6,345	$ 900	$ 900
Gross carrying value, indefinite items																			28,600	28,600	3,600	3,600
Gross carrying value, excluding goodwill		284,248	284,027
Accumulated amortization		(82,808)	(78,771)		(35,173)		(32,930)	(39,308)		(37,848)	(5,342)		(5,211)	(2,085)		(1,882)	(900)	(900)	0	0	0	0
Net carrying value, finite intangible items					115,161		117,368	47,271		48,797	2,548		2,428	4,260		4,463	0	0
Net carrying value, indefinite items																			28,600	28,600	3,600	3,600
Net carrying value, excluding goodwill	$ 214,673	$ 201,440	$ 205,256	$ 147,363
Weighted avg useful life	3 years				8 years 9 months 18 days	10 years 2 months 12 days		9 years 1 month 6 days	11 years 10 months 24 days		8 years 3 months 18 days	8 years 4 months 24 days		6 years 7 months 6 days	8 years		3 years