Property, Plant and Equipment, Net by Geographic Region (Detail) - USD ($) $ in Thousands	May 31, 2016	May 31, 2015
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 582,838	$ 513,190
UNITED STATES
Segment Reporting Information [Line Items]
Property, plant and equipment, net	506,649	439,296
Europe
Segment Reporting Information [Line Items]
Property, plant and equipment, net	49,529	50,520
Mexico
Segment Reporting Information [Line Items]
Property, plant and equipment, net	4,903	5,030
CANADA
Segment Reporting Information [Line Items]
Property, plant and equipment, net	3,711	4,284
Other Countries
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 18,046	$ 14,060