Share-Based Payments (Details 3) - $ / shares	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Restricted Shares And Deferred Stock Units [Member]
Weighted-average grant date fair values of the equity awards
Restricted Shares and Deferred Stock Units and Performance Units	146,290	66,514	83,188
Weighted-Average Grant Date Fair Value Per Share	$ 131.96	$ 135.10	$ 110.66
Performance Units [Member]
Weighted-average grant date fair values of the equity awards
Restricted Shares and Deferred Stock Units and Performance Units	130,939	171,907	194,786
Weighted-Average Grant Date Fair Value Per Share	$ 133.01	$ 135.53	$ 113.70