Note 21 - Changes in Accumulated Other Comprehensive Income (Loss) by Component (1) - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance		$ 245,189	$ 226,460	$ 215,053
Unrealized gain (loss) on securities		3,461	3,976	(319)
Total other comprehensive income (loss)		4,586	(2,778)	(215)
Reclassification due to the adoption of ASU 2018-02
Net unrealized holding losses on securities transferred from available-for-sale to held-to-maturity			(6,855)
Balance		249,168	245,189	226,460
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	[1]	(4,736)	(7,150)	(6,831)
Unrealized gain (loss) on securities	[1]	4,284	3,927	(413)
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]	(823)	49	94
Total other comprehensive income (loss)	[1]	3,461	3,976	(319)
Total change in accumulated other comprehensive income	[1]	3,461	2,414	(319)
Reclassification due to the adoption of ASU 2018-02	[1]		(1,562)
Net unrealized holding losses on securities transferred from available-for-sale to held-to-maturity	[1]
Balance	[1]	(1,275)	(4,736)	(7,150)
Accumulated Net Investment Gain (Loss) on Securities Transferred from Available-for-Sale to Held-to-Maturity [Member]
Balance	[1]	(7,191)	(359)	(463)
Unrealized gain (loss) on securities	[1]
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]	1,125	101	104
Total other comprehensive income (loss)	[1]	1,125	(6,754)	104
Total change in accumulated other comprehensive income	[1]	1,125	(6,832)	104
Reclassification due to the adoption of ASU 2018-02	[1]		(78)
Net unrealized holding losses on securities transferred from available-for-sale to held-to-maturity	[1]		(6,855)
Balance	[1]	(6,066)	(7,191)	(359)
AOCI Attributable to Parent [Member]
Balance	[1]	(11,927)	(7,509)	(7,294)
Unrealized gain (loss) on securities	[1]	4,284	3,927	(413)
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]	302	150	198
Total other comprehensive income (loss)	[1]	4,586	(2,778)	(215)
Total change in accumulated other comprehensive income	[1]	4,586	(4,418)	(215)
Reclassification due to the adoption of ASU 2018-02	[1]		(1,640)
Net unrealized holding losses on securities transferred from available-for-sale to held-to-maturity	[1]		(6,855)
Balance	[1]	$ (7,341)	$ (11,927)	$ (7,509)

[1] All amounts are net of tax. Amounts in parentheses indicate reductions to other comprehensive income.

[2] Reclassification amounts are reported as gains/losses on sales of investment securities, impairment losses, and amortization of net unrealized losses on the Consolidated Statement of Income.