Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 777,017	$ 780,304
Held-to-maturity securities, fair value	$ 43,227	$ 45,853
Preferred stock, shares authorized	50,000	50,000
Preferred stock, shares issued	0	0
Common stock, shares authorized	24,000,000	24,000,000
Common stock, shares issued	18,939,091	18,931,200
Treasury stock, shares	795,758	586,688