Note 15 - Balance Sheet Offsetting - Financial Instruments that are Eligible for Offset in the Consolidated Balance Sheet (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Securities sold under agreements to repurchase, net	$ 150,000,000	$ 350,000,000
Securities sold under agreements to repurchase, collateral posted	(150,000,000)	(350,000,000)
Derivative liabilities, gross	4,771,000	3,744,000
Derivative liabilities, net	4,771,000	3,744,000
Derivatives, collateral posted	(4,771,000)	(3,744,000)
Derivative assets, gross	1,608,000	938,000
Derivative assets, net	1,608,000	938,000
Derivative assets not offset	1,608,000	938
Securities sold under agreements to repurchase, gross	$ 150,000,000	$ 350,000,000