Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Securities available-for-sale, amortized cost	$ 1,322,579	$ 1,267,731
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	89,920,909	89,826,317
Common stock, shares outstanding (in shares)	80,362,840	80,501,948
Treasury stock shares (in shares)	9,558,069	9,324,369