Note 14 - Shareholders' Equity and Regulatory Matters - (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Oct. 12, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders' Equity Attributable to Parent		$ 179,935	$ 113,559	$ 112,449	$ 78,845
Common Stock, Dividends, Per Share, Cash Paid		$ 0.23	$ 0.15
Private Placement [Member]
Stock Issued During Period, Shares, New Issues	3,299,925
Sale of Stock, Price Per Share	$ 20
Proceeds From Issuance of Private Placement, Net	$ 62,500