Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Summary of Gains and Losses on Interest Rate Swap (Parenthetical) (Detail)

v3.19.2
Financial Instruments - Summary of Gains and Losses on Interest Rate Swap (Parenthetical) (Detail) - USD ($)
$ in Thousands
12 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Apr. 30, 2017
Interest Rate Swap      
Derivative [Line Items]      
Gains (Losses) recognized in OCI, tax effects $ (281) $ 828 $ (406)