Stockholders' Equity - Reconciliation of Net Income/(Loss) Amounts and Weighted Average Number of Common and Common Equivalent Shares Used to Determine Basic and Diluted Earnings/(Loss) per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Net income/(loss)
Income from continuing operations	$ 49,118	$ 343	$ 92,417	$ 2,528
Income/(loss) from discontinued operations, net of tax	3,123	950	8,209	(3,343)
Net income/(loss)	$ 52,241	$ 1,293	$ 100,626	$ (815)
Weighted average shares outstanding — Basic	55,914	54,912	55,691	54,847
Effect of dilutive stock awards	617	512	784
Weighted average shares outstanding — Diluted	56,531	55,424	56,475	54,847
Earnings/(loss) per share — Basic
Income from continuing operations	$ 0.88	$ 0.01	$ 1.66	$ 0.05
Income/(loss) from discontinued operations	0.05	0.01	0.15	(0.06)
Net income/(loss)	0.93	0.02	1.81	(0.01)
Earnings/(loss) per share — Diluted
Income from continuing operations	0.87	0.01	1.64	0.05
Income/(loss) from discontinued operations	0.05	0.01	0.14	(0.06)
Net income/(loss)	$ 0.92	$ 0.02	$ 1.78	$ (0.01)