Note 8 - Changes in Accumulated Other Comprehensive Income (Loss) By Component (1) - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Balance	[1]	$ (7,294)	$ (3,165)	$ (3,165)
Unrealized gain on securities	[1]	623	2,122	(3,853)
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]	27	(152)	(276)
Net current-period other comprehensive income	[1]	650	1,970	(4,129)
Balance	[1]	(6,644)	(1,195)	(7,294)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Balance	[1]	(6,831)	(2,562)	(2,562)
Unrealized gain on securities	[1]	623	2,122	(3,853)
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]		(189)	(416)
Net current-period other comprehensive income	[1]	623	1,933	(4,269)
Balance	[1]	(6,208)	(629)	(6,831)
Accumulated Net Investment Gain (Loss) on Securities Transferred from Available-for-Sale to Held-to-Maturity [Member]
Balance	[1]	(463)	(603)	(603)
Unrealized gain on securities	[1]
Amounts reclassified from accumulated other comprehensive income to net income (2)	[1],[2]	27	37	140
Net current-period other comprehensive income	[1]	27	37	140
Balance	[1]	$ (436)	$ (566)	$ (463)

[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.