Note 20 - Commitments - (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Rent Expense	$ 1.8	$ 1.5	$ 1.4
Federal Home Loan Bank Advances [Member]
Letters of Credit Outstanding, Amount	81.0	$ 81.0
Letter of Credit of $11 Million, Expires in March 2018 [Member]
Letters of Credit Outstanding, Amount	11.0
Letter of Credit of $5 Million Expires in May 2018 [Member]
Letters of Credit Outstanding, Amount	5.0
Letter of Credit of $40 Million Expires in December 2018 [Member]
Letters of Credit Outstanding, Amount	40.0
Letter of Credit of $25 Million Expires in December 2018 [Member]
Letters of Credit Outstanding, Amount	$ 25.0
Minimum [Member]
Non-cancelable Operating Lease Terms	1 year
Maximum [Member]
Non-cancelable Operating Lease Terms	10 years