Note 7 - Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Dec. 31, 2022		Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Balance as of September 30, 2022	$ (44,111)		$ 2,927	$ (27,982)	$ 4,493
Balance as of September 30, 2022	9,263		(615)	5,876	(943)
Balance as of September 30, 2022	(34,848)		2,312	(22,106)	3,550
Unrealized holding gains on available-for-sale securities arising during the period, before tax	5,429		(922)	(10,711)	(2,488)
Unrealized holding gains on available-for-sale securities arising during the period, tax	(1,140)		194	2,249	522
Unrealized holding gains on available-for-sale securities arising during the period, net	4,289		(728)	(8,462)	(1,966)
Amounts reclassified from accumulated other comprehensive income, before tax	4	[1],[2]	(2)	15	(2)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(1)	[1],[2]	0	(3)	0
Amounts reclassified from accumulated other comprehensive income, net	3	[1],[2]	(2)	12	(2)
Net current period other comprehensive gain, before tax	5,433		(924)	(10,696)	(2,490)
Net current period other comprehensive gain, tax	(1,141)		194	2,246	522
Net current period other comprehensive gain, net	4,292		(730)	(8,450)	(1,968)
Accumulated other comprehensive income (loss), before tax	(38,678)		2,003	(38,678)	2,003
Accumulated other comprehensive income (loss), tax	8,122		(421)	8,122	(421)
Accumulated other comprehensive income (loss), net	$ (30,556)		$ 1,582	$ (30,556)	$ 1,582

[1] Income tax expense

[2] Securities (gains) losses, net