Schedule of Consideration Transferred and Fair Value Assigned to Assets Acquired And Liabilities Assumed (Detail) (TWB, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2013
TWB
Consideration Transferred:
Cash consideration	$ 17,869
Fair value of previously held interest in TWB	72,369
Total consideration	90,238
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Cash and cash equivalents	70,826
Accounts receivable	52,012
Inventories	20,403
Prepaid expenses and other current assets	4,027
Intangible assets	22,028
Other noncurrent assets	103
Property, plant and equipment	52,390
Total identifiable assets	221,789
Accounts payable	(50,642)
Accrued liabilities	(6,431)
Deferred taxes	(2,109)
Net assets	162,607
Noncontrolling interest	(72,369)
Total consideration	$ 90,238