Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
Jul. 31, 2021	Jul. 31, 2020	Apr. 30, 2021
Selling, general and administrative expenses
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Expense related to equity based compensation arrangements	$ 1,200	$ 1,000
Stock Appreciation Rights
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Award liability as of beginning of period	26,795
Amounts redeemed	0
Change in fair value	892
Award liability as of end of period	27,687
Current liabilities related to plans	1,521		$ 1,305
Long-term liabilities related to plans	26,166		25,490
Deferred Compensation
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Award liability as of beginning of period	1,875
Amounts redeemed	0
Change in fair value	51
Award liability as of end of period	1,926
Current liabilities related to plans	0		0
Long-term liabilities related to plans	1,926		1,875
Redeemable Noncontrolling Interests
Deferred Compensation Liability, Current and Noncurrent [Roll Forward]
Award liability as of beginning of period	9,373
Amounts redeemed	0
Change in fair value	259
Award liability as of end of period	9,632
Current liabilities related to plans	0		0
Long-term liabilities related to plans	$ 9,632		$ 9,373

Deferred Compensation Liability, Current and Noncurrent

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- Definition

Amount of expense on certain equity based compensation arrangements, such as stock appreciation rights, deferred compensation agreements and liabilities to noncontrolling interest holders.

+ References

No definition available.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable within one year (or the operating cycle, if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable after one year (or the operating cycle, if longer).

+ References

No definition available.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements.

+ References

No definition available.

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- Definition

Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

+ References

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- Definition

Amount of cash paid to settle liability for award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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