Restatement - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2012		Aug. 31, 2011
Estimated Loss on Contingency	$ 11,418	[1]
Net income	30,619	[1]	83,340
Adjustments
Estimated Loss on Contingency	11,418
Net income	$ (7,248)

[1] Restated