Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Cost of available for sale securities	$ 1,680,299	$ 1,584,703
Fair value of held to maturity securities	$ 289,446	$ 294,513
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	24,519,928	22,435,693
Treasury stock shares	65	0
Series C Senior Non-Cumulative Perpetual Convertible Preferred Stock
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares outstanding	0	81,698
Series D Senior Non-Cumulative Perpetual Convertible Preferred Stock
Preferred stock, par value (in dollars per share)	$ 1	$ 0
Preferred stock, shares authorized	3,000	0
Preferred stock, shares issued	3,000	0
Preferred stock, shares outstanding	3,000	0