Note 6 - Accumulated Other Comprehensive Income - Components of Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2017		Dec. 31, 2016	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2016
Accumulated other comprehensive income (loss), before tax		$ 110	$ (246)		$ 110		$ (246)	$ 741	$ 675	$ 3,095	$ 3,621
Accumulated other comprehensive income (loss), tax		(37)	(83)		(37)		(83)	(252)	(230)	(1,053)	(1,232)
Accumulated other comprehensive income		73	(163)		73		(163)	$ 489	$ 445	$ 2,042	$ 2,389
Unrealized holding gain on available-for-sale securities arising during the period, before tax		(631)	(3,319)		(527)		(3,742)
Unrealized holding loss on available-for-sale securities arising during the period, tax		215	1,128		180		1,272
Unrealized holding gain on available-for-sale securities arising during the period, net		(416)	(2,191)		(347)		(2,470)
Amounts reclassified from accumulated other comprehensive income, before tax			(22)	[1],[2]	(38)	[1],[2]	(125)
Amounts reclassified from accumulated other comprehensive income, tax	[1],[2]		8		13		43
Amounts reclassified from accumulated other comprehensive income, net	[1],[2]		(14)		(25)		(82)
Net current period other comprehensive income (loss), before tax			(3,341)		(565)		(3,867)
Net current period other comprehensive loss, tax			1,136		193		1,315
Net current period other comprehensive income (loss), net		(416)	(2,205)		(372)		(2,552)
Amounts reclassified from accumulated other comprehensive income, before tax			(22)	[1],[2]	(38)	[1],[2]	(125)
Amounts reclassified from accumulated other comprehensive income, tax	[1],[2]		$ 8		$ 13		$ 43

[1] Income tax expense

[2] Securities gain, net