Note 2 - Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance	$ 175,698	$ 172,929	$ 170,055
Other comprehensive (loss) income	(6,190)	(2,093)	8,087
Balance	184,066	175,698	172,929
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Balance	3,219	5,174
Other comprehensive (loss) income before reclassifications	(3,983)	(1,844)
Amounts reclassified from accumulated other comprehensive income	(2,599)	(111)
Other comprehensive (loss) income	(6,582)	(1,955)
Balance	(3,363)	3,219	5,174
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(437)	(299)
Other comprehensive (loss) income before reclassifications	356	(198)
Amounts reclassified from accumulated other comprehensive income	36	60
Other comprehensive (loss) income	392	(138)
Balance	(45)	(437)	(299)
AOCI Attributable to Parent [Member]
Balance	2,782	4,875	(3,212)
Other comprehensive (loss) income before reclassifications	(3,627)	(2,042)
Amounts reclassified from accumulated other comprehensive income	(2,563)	(51)
Other comprehensive (loss) income	(6,190)	(2,093)	8,087
Balance	$ (3,408)	$ 2,782	$ 4,875