Fair Value Measurements (Fair Value Of Assets On Recurring Basis) (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Apr. 30, 2020	Apr. 30, 2019
LEVEL 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		$ 3,104
LEVEL 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		0
LEVEL 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		0
Money Market Funds [Member] | LEVEL 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 773	1,500
Money Market Funds [Member] | LEVEL 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	0	0
Money Market Funds [Member] | LEVEL 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	0	0
Mutual Funds [Member] | LEVEL 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		1,604
Foreign exchange forward contracts	0
Mutual Funds [Member] | LEVEL 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		0
Foreign exchange forward contracts	(1,102)
Mutual Funds [Member] | LEVEL 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		$ 0
Foreign exchange forward contracts	$ 0