Amounts Used In Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	12 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted-average number of basic shares outstanding	20,500	20,439	20,203
Stock options, stock units and performance awards	419	633	759
Assumed conversion of non-controlling interest	732	213	204
Total shares and dilutive securities	21,651	21,285	21,166