CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Available for sale
Securities available for sale, amortized cost	$ 2,437,513	$ 2,306,741
Held to maturity
Securities held to maturity, fair value	$ 118,198	$ 138,879
Stockholders' equity
Common Stock, Par or Stated Value Per Share	$ 1.25	$ 1.25
Common Stock, Shares Authorized	80,000,000	80,000,000
Common Stock, Shares, Issued	37,934,819	37,887,662
Treasury Stock, Shares	4,983,645	4,064,405