Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2022	Jan. 31, 2022	Oct. 31, 2021	Jul. 31, 2021	Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 76,496	$ 61,383	$ 74,361	$ 61,202	$ 33,746	$ 16,126	$ 28,469	$ 27,219	$ 273,442	$ 105,560	$ 23,381
Less: Net income allocated to participating securities									0	0	74
Net income attributable to common stockholders									$ 273,442	$ 105,560	$ 23,307
Basic earnings per common share:
Basic weighted average common shares outstanding (in shares)	42,977	43,094	43,135	43,089	42,994	42,726	42,723	42,624	43,075	42,765	41,853
Basic earnings per common share (in dollars per share)	$ 1.78	$ 1.42	$ 1.72	$ 1.42	$ 0.78	$ 0.38	$ 0.67	$ 0.64	$ 6.35	$ 2.47	$ 0.56
Diluted earnings per common share:
Basic weighted average common shares outstanding (in shares)	42,977	43,094	43,135	43,089	42,994	42,726	42,723	42,624	43,075	42,765	41,853
Add: Common Stock Equivalents									823	578	651
Diluted weighted average common shares outstanding (in shares)	43,776	43,945	43,894	43,972	43,828	43,361	43,174	43,017	43,898	43,343	42,504
Diluted earnings per common share (in dollars per share)	$ 1.75	$ 1.40	$ 1.69	$ 1.39	$ 0.77	$ 0.37	$ 0.66	$ 0.63	$ 6.23	$ 2.44	$ 0.55
Shares were not included in the calculation of Diluted loss per common share
Anti-dilutive shares (in shares)										300	800