Note 5 - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss		$ (12,135)	$ (6,191)
Tax effect		2,548	1,300
Stranded tax effect	[1]		805
Accumulated other comprehensive loss, net of tax		(9,587)	(4,086)
Accumulated Net Investment Loss Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss		(12,130)	(6,165)
Accumulated Other-than-Temporary Impairment Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss		$ (5)	$ (26)

[1] Refer to Note 2, ASU 2018-02