Note 10 - Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Dec. 31, 2016
Accumulated other comprehensive income (loss)		$ (659)		$ (254)	$ (659)	$ (254)
Other comprehensive income (loss), net of tax	$ 915	256	$ 519	1,446	1,171	(405)
Accumulated other comprehensive income (loss)	512		1,711		512	(659)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated other comprehensive income (loss)		(659)		1,142	(659)	1,142
Other comprehensive income (loss), net of tax	915	$ 256	519	50
Accumulated other comprehensive income (loss)	$ 512		1,711		$ 512	(659)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated other comprehensive income (loss)				(1,396)		$ (1,396)
Other comprehensive income (loss), net of tax				$ 1,396
Accumulated other comprehensive income (loss)