Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Statement Of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 7,434,480	$ 7,777,950
Held to maturity securities, allowance for credit losses	2,828	2,407
Held to Maturity, Fair value	$ 5,234,236	$ 5,280,659
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	48,517,750	48,319,404
Treasury stock, shares	6,538,980	6,737,326