Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Jan. 31, 2023	Oct. 31, 2022	Jul. 31, 2022	Jan. 31, 2022	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2023	Jan. 31, 2022
Computation of basic and diluted earnings per share of common stock
Net income	$ 64,775	$ 103,153	$ 89,470	$ 61,383	$ 74,361	$ 61,202	$ 257,398	$ 196,946
Basic earnings per common share:
Basic weighted average common shares outstanding (in shares)	41,578			43,094			42,119	43,106
Basic earnings per common share (in dollars per share)	$ 1.56			$ 1.42			$ 6.11	$ 4.57
Diluted earnings per common share:
Basic weighted average common shares outstanding (in shares)	41,578			43,094			42,119	43,106
Add: Common Stock Equivalents (in shares)	654			851			693	831
Diluted weighted average common shares outstanding (in shares)	42,232			43,945			42,812	43,937
Diluted earnings per common share (in dollars per share)	$ 1.53			$ 1.40			$ 6.01	$ 4.48
Shares were not included in the calculation of Diluted loss per common share
Anti-dilutive shares (in shares)	0			0			0	0