Note 6 - Comprehensive Income - Components of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 31, 2024	Jul. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Oct. 31, 2024	Oct. 31, 2023
Change in unrealized gains on available-for-sale fixed income securities					$ 227	$ (837)
Change in unrealized gains on available-for-sale fixed income securities					(48)	177
Change in unrealized gains on available-for-sale fixed income securities					179	(660)
Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, before Tax, Portion Attributable to Parent					227	(837)
Other comprehensive income (loss), available-for-sale securities, tax expense					(48)	177
Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	$ 2	$ 177	$ (448)	$ (212)	$ 179	$ (660)

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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