Note 2 - Significant Accounting Policies - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance	$ (2,324)
Other comprehensive income (loss) before reclassifications	1,451
Losses (gains) reclassified from accumulated other comprehensive income (loss)	(16)
Other comprehensive income (loss)	1,435	$ (450)	$ (22)
Balance	(889)	(2,324)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	(1,633)
Other comprehensive income (loss) before reclassifications	1,494
Losses (gains) reclassified from accumulated other comprehensive income (loss)	73
Other comprehensive income (loss)	1,567
Balance	(66)	(1,633)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Balance	(3)
Other comprehensive income (loss) before reclassifications	108
Losses (gains) reclassified from accumulated other comprehensive income (loss)	(105)
Other comprehensive income (loss)	3
Balance		(3)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(361)
Other comprehensive income (loss) before reclassifications	(141)
Losses (gains) reclassified from accumulated other comprehensive income (loss)	16
Other comprehensive income (loss)	(125)
Balance	(486)	(361)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(327)
Other comprehensive income (loss) before reclassifications	(10)
Losses (gains) reclassified from accumulated other comprehensive income (loss)
Other comprehensive income (loss)	(10)
Balance	$ (337)	$ (327)