Note 12 - Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive income (loss), beginning balance	$ 632	$ 2,085	$ (2,217)
Other comprehensive income (loss) before reclassifications	(2,131)	(1,520)	4,296
Amounts reclassified from accumulated other comprehensive income		67	6
Other comprehensive (loss) income	(2,131)	(1,453)	4,302
Accumulated other comprehensive income (loss), ending balance	(1,499)	632	2,085
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated other comprehensive income (loss), beginning balance	965	2,456	(1,973)
Other comprehensive income (loss) before reclassifications	(2,176)	(1,558)	4,423
Amounts reclassified from accumulated other comprehensive income		67	6
Other comprehensive (loss) income	(2,176)	(1,491)	4,429
Accumulated other comprehensive income (loss), ending balance	(1,211)	965	2,456
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated other comprehensive income (loss), beginning balance	(60)	16	16
Other comprehensive income (loss) before reclassifications	44	(76)
Amounts reclassified from accumulated other comprehensive income
Other comprehensive (loss) income	44	(76)
Accumulated other comprehensive income (loss), ending balance	(16)	(60)	16
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated other comprehensive income (loss), beginning balance	(273)	(387)	(260)
Other comprehensive income (loss) before reclassifications	1	114	(127)
Amounts reclassified from accumulated other comprehensive income
Other comprehensive (loss) income	1	114	(127)
Accumulated other comprehensive income (loss), ending balance	$ (272)	$ (273)	$ (387)