XML 124 R102.htm IDEA: XBRL DOCUMENT v3.21.2
Income Taxes - Tax Cuts and Jobs Act (Details)
12 Months Ended
Apr. 30, 2021
Apr. 30, 2020
Apr. 30, 2019
Income Taxes      
U.S. federal statutory income tax rate (as a percent) 21.00% 21.00% 21.00%