Earnings Per Share (Narrative) (Details) - USD ($)	12 Months Ended
Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018	Aug. 22, 2019	Nov. 28, 2018	Nov. 30, 2016
Earnings Per Share [Abstract]
Potentially dilutive shares	0		0
Stock Repurchase Program, Authorized Amount	$ 0			$ 50,000,000	$ 14,000,000	$ 50,000,000
Treasury Stock, Shares, Acquired		745,232	309,612
Treasury Stock, Value, Acquired, Cost Method		$ 50,000,000.0	$ 29,000,000.0

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section S99
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-Subparagraph (SX 210.3-04)
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Balance Type:	debit
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