CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Class A [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividend (in dollars per share)	$ 1.37	$ 1.36	$ 1.32
Class B [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividend (in dollars per share)	$ 1.37	$ 1.36	$ 1.32