Summary of Other Intangible Assets by Class (Detail) - USD ($) $ in Thousands	May 31, 2016	May 31, 2015
Other Intangible Assets [Line Items]
Indefinite-lived intangible assets, cost	$ 14,501	$ 12,601
Cost	145,696	166,664
Definite-lived intangible assets, cost	131,195	154,063
Accumulated Amortization	49,532	47,547
Trademarks
Other Intangible Assets [Line Items]
Indefinite-lived intangible assets, cost	14,501	12,601
Customer relationships
Other Intangible Assets [Line Items]
Definite-lived intangible assets, cost	96,072	119,871
Accumulated Amortization	35,561	34,421
Non-compete agreements
Other Intangible Assets [Line Items]
Definite-lived intangible assets, cost	9,422	14,221
Accumulated Amortization	6,237	6,897
Technology / know-how
Other Intangible Assets [Line Items]
Definite-lived intangible assets, cost	21,689	15,633
Accumulated Amortization	3,865	2,350
Other Intangible Assets
Other Intangible Assets [Line Items]
Definite-lived intangible assets, cost	4,012	4,338
Accumulated Amortization	$ 3,869	$ 3,879