Note 6 - Comprehensive Income - Components of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jan. 31, 2025	Oct. 31, 2024	Jul. 31, 2024	Jan. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Jan. 31, 2025	Jan. 31, 2024
Change in unrealized gains on available-for-sale fixed income securities, amount before tax							$ 218	$ (508)
Change in unrealized gains on available-for-sale fixed income securities, tax (expense) benefit							(46)	106
Change in unrealized gains on available-for-sale fixed income securities, amount net of tax							172	(402)
Other comprehensive income (loss), available-for-sale securities, amount before tax							218	(508)
Other comprehensive income (loss), available-for-sale securities, tax expense							(46)	106
Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	$ (7)	$ 2	$ 177	$ 258	$ (448)	$ (212)	$ 172	$ (402)

Amount, before tax and after reclassification adjustment, of gain (loss) in value of unsold investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), attributable to parent.

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