Comprehensive Income (Loss) - Additional Information (Detail)	12 Months Ended
	May. 31, 2015 USD ($)
Other Comprehensive Income (Loss) [Line Items]
Losses in accumulated other comprehensive income expected to be reclassified into net earnings	$ (12,619,000)
Losses in accumulated other comprehensive income expected to be reclassified into net earnings, tax	$ 7,518,000