Note 10 - Accumulated Other Comprehensive Income (Loss) - Significant Amounts Reclassified Out of Each Component of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other than temporary impairment losses					$ (508)
Provision for income taxes	187	392		735	978
Net income	1,161	$ 1,707		3,935	3,704
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Unrealized gains and losses on available-for-sale securities	(4)			(34)	350
Other than temporary impairment losses					(508)
Provision for income taxes	1			7	54
Net income	$ (3)			$ (27)	$ (104)