Note 6 - Qualified Affordable Housing Partnership Investments (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Proportional Amortization Method Qualified Affordable Housing Project Investments	$ 3,882		$ 3,882		$ 4,217
Proportional Amortization Method Qualified Affordable Housing Project Investments Unfunded Liability Obligation	467		$ 467		485
Qualified Affordable Housing Project Investments Term			18 years
Proportional Amortization Method Qualified Affordable Housing Project Investments Amortization	$ 164	$ 180	$ 335	$ 360	$ 598
Minimum [Member]
Qualified Affordable Housing Project Investments Return Rate			5.00%
Maximum [Member]
Qualified Affordable Housing Project Investments Return Rate			8.00%