XML 89 R74.htm IDEA: XBRL DOCUMENT v3.7.0.1
Stockholders' Equity - Share Based Payment Award Performance Shares Valuation Assumptions (Parenthetical) (Detail)
12 Months Ended
Apr. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Performance based restricted stock unit performance period 3 years
PSUs  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Performance based restricted stock unit performance period 3 years