Note 8 - Changes in Accumulated Other Comprehensive Income (Loss) By Component (1) - Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended		9 Months Ended				12 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015		Dec. 31, 2015
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Balance	[1]			$ (2,562,000)		$ 82,000		$ 82,000
Unrealized gain on securities	[1]			2,170,000		(460,000)		(2,577,000)
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]			(416,000)		(45,000)		(67,000)
Net current-period other comprehensive income	[1]			1,754,000		(505,000)		(2,644,000)
Balance	[1]	$ (808,000)	$ (423,000)	(808,000)		(423,000)		(2,562,000)
Accumulated Net Investment Gain (Loss) on Securities Transferred from Available-for-Sale to Held-to-Maturity [Member]
Balance	[1]			(603,000)		(714,000)		(714,000)
Unrealized gain on securities	[1]
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]			85,000		82,000		111,000
Net current-period other comprehensive income	[1]			85,000		82,000		111,000
Balance	[1]	(518,000)	(632,000)	(518,000)		(632,000)		(603,000)
Balance	[1]			(3,165,000)		(632,000)		(632,000)
Unrealized gain on securities	[1]			2,170,000		(460,000)		(2,577,000)
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]			(331,000)		37,000		44,000
Net current-period other comprehensive income		(669,000)	289,000	1,839,000	[1]	(423,000)	[1]	(2,533,000)	[1]
Balance	[1]	$ (1,326,000)	$ (1,055,000)	$ (1,326,000)		$ (1,055,000)		$ (3,165,000)

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

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