Significant Accounting Policies - Reconciliation of Net Income/(Loss) Amounts and Weighted Average Number of Common and Common Equivalent Shares Used to Determine Basic and Diluted (Loss)/Earnings per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Net income/(loss)
Income from continuing operations	$ 243,571	$ 27,653	$ 24,920
Income/(loss) from discontinued operations	8,478	(88,883)	(6,510)
Net income/(loss)	$ 252,049	$ (61,230)	$ 18,410
Weighted average shares outstanding — Basic	54,613	54,983	54,483
Effect of dilutive stock awards	739	682	733
Weighted average shares outstanding — Diluted	55,352	55,665	55,216
Earnings/(loss) per share — Basic
Income from continuing operations	$ 4.46	$ 0.50	$ 0.46
Income/(loss) from discontinued operations	0.16	(1.62)	(0.12)
Basic - net income/(loss)	4.62	(1.11)	0.34
Earnings/(loss) per share — Diluted
Income from continuing operations	4.40	0.50	0.45
Income/(loss) from discontinued operations	0.15	(1.60)	(0.12)
Diluted - net income/(loss)	$ 4.55	$ (1.10)	$ 0.33

Significant Accounting Policies - Reconciliation of Net Income/(Loss) Amounts and Weighted Average Number of Common and Common Equivalent Shares Used to Determine Basic and Diluted (Loss)/Earnings per Common Share (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands

12 Months Ended

Apr. 30, 2021

Apr. 30, 2020

Apr. 30, 2019

Net income/(loss)

Income from continuing operations

$ 243,571

$ 27,653

$ 24,920

Income/(loss) from discontinued operations

8,478

(88,883)

(6,510)

Net income/(loss)

$ 252,049

$ (61,230)

$ 18,410

Weighted average shares outstanding — Basic

54,613

54,983

54,483

Effect of dilutive stock awards

739

682

733

Weighted average shares outstanding — Diluted

55,352

55,665

55,216

Earnings/(loss) per share — Basic

Income from continuing operations

$ 4.46

$ 0.50

$ 0.46

Income/(loss) from discontinued operations

0.16

(1.62)

(0.12)

Basic - net income/(loss)

4.62

(1.11)

0.34

Earnings/(loss) per share — Diluted

Income from continuing operations

4.40

0.50

0.45

Income/(loss) from discontinued operations

0.15

(1.60)

(0.12)

Diluted - net income/(loss)

$ 4.55

$ (1.10)

$ 0.33

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=121326447&loc=d3e1448-109256

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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