Note 16 - Regulatory Capital Requirements and Restrictions on Dividends (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018 security	Oct. 27, 2016 USD ($)
Regulatory Capital Requirements and Restrictions on Dividends
Annual phase in percentage of capital conservation buffer	0.625%
Capital required for capital adequacy to risk weighted assets with capital conservation buffer fully phased in		10.50%
Tier One risk based capital required for capital adequacy to risk weighted assets with capital conservation buffer fully phased in		8.50%
Common equity tier one risk based capital required for capital adequacy to risk weighted assets with capital conservation buffer fully phased in		7.00%
Shelf registration maximum value of equity authorized for issuance | $			$ 100.0
The number of junior subordinated private placement debentures issued		4
The number of junior subordinated private placement debentures assumed		3