Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Securities Available-for-sale, Amortized Cost	$ 1,172,175,000	$ 834,850,000
Securities, Available-for-sale, Allowance for Credit Losses	$ 0
Common Stock, stated value (in dollars per share)	$ 1	$ 1
Common Stock, shares authorized (in shares)	45,000,000	45,000,000