Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Securities available for sale, amortized cost	$ 1,161,098	$ 1,001,034
Investment securities – held to maturity	$ 15,186	$ 12,661
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	24,713,968	24,650,051
Common stock, shares outstanding (in shares)	19,960,294	20,126,296
Treasury stock, shares (in shares)	4,753,674	4,523,755