CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Securities Available-for-Sale, Amortized Cost	$ 997,074,000	$ 834,850,000
Securities Available-for-Sale, Allowance for Credit Losses	$ 0
Common stock, stated value (USD per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	45,000,000	45,000,000