XML 15 R42.htm IDEA: XBRL DOCUMENT v3.19.2
Defined Benefit Pension Plans - Pension Expenses (Detail) - USD ($)
$ in Thousands
3 Months Ended
Jul. 31, 2019
Jul. 31, 2018
Retirement Benefits [Abstract]    
Service cost $ 0 $ 0
Interest cost 208 215
Expected return on plan assets (355) (362)
Recognition of net loss 260 221
Net periodic pension expense $ 113 $ 74