CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Securities, available-for-sale, at fair value	$ 1,887,702,000	$ 1,865,732,000
Securities, available-for-sale, at amortized cost	$ 0	$ 0
Common stock, stated value (in shares)	$ 1	$ 1
Common stock, shares authorized (in shares)	45,000,000	45,000,000