Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement Of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 7,207,331	$ 7,692,860
Held to maturity securities, allowance for credit losses	3,820	3,258
Held to Maturity, Fair value	$ 5,025,138	$ 5,183,367
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	55,056,730	55,056,730
Common stock, shares outstanding	48,743,348	48,554,127
Treasury stock, shares	6,313,382	6,502,603