CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Securities available-for-sale, amortized cost	$ 1,638,341	$ 1,741,153
Securities available-for-sale, allowance for credit losses	0	0
Securities held-to-maturity, allowance for credit losses	0	0
Securities held-to-maturity	$ 561,333	$ 0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	21,778,731	21,668,644
Treasury stock (in shares)	1,249,607	649,607