XML 69 R54.htm IDEA: XBRL DOCUMENT v3.7.0.1
Net Sales - Additional Information (Detail)
12 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Apr. 30, 2015
Disclosure Net Sales [Abstract]      
Export sales as percentage of revenue 3.00% 3.00% 4.00%