Equity - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended			23 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015	May 31, 2016	Jun. 25, 2014
Class of Stock [Line Items]
Purchases of common shares (in shares)			2,453,855
Purchases and retirement of common shares (in shares)	0	3,500,000	4,176,187
Repurchase of common shares		$ 99,847	$ 127,360
Deferred compensation obligation credited to common share option	$ 1,259	$ 960		$ 960
Stock repurchase on June 25, 2014
Class of Stock [Line Items]
Common Stock remaining shares authorized for repurchase	4,046,145
Purchases of common shares (in shares)				5,953,855
Maximum | Stock repurchase on June 25, 2014
Class of Stock [Line Items]
Common Stock shares authorized for repurchase					10,000,000