Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Held to maturity securities	$ 2,231,335	$ 2,435,663
Loans held for sale	29,960	18,929
Derivative financial instruments, Financial assets	55,113	71,893
Derivative financial instruments, Financial liabilities	45,328	54,707
Total Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	1,117,111	1,514,625
Available for sale securities	5,636,676	5,161,491
Held to maturity securities	2,083,072	2,233,526
Loans, net	22,999,446	22,562,577
Loans held for sale	30,760	21,525
Derivative financial instruments, Financial assets	71,083	73,840
Deposits	29,036,525	29,482,628
Federal funds purchased	110,300	300
Securities sold under agreements to repurchase	534,627	638,715
FHLB short-term borrowings	400,000
Long-term debt	175,014	174,660
Derivative financial instruments, Financial liabilities	118,517	160,623
Total Fair Value [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	1,116,738	1,514,216
Total Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	373	409
Available for sale securities	5,636,676	5,161,491
Held to maturity securities	2,083,072	2,233,526
Loans held for sale	30,760	21,525
Derivative financial instruments, Financial assets	71,083	73,840
Federal funds purchased	110,300	300
Securities sold under agreements to repurchase	534,627	638,715
FHLB short-term borrowings	400,000
Long-term debt	175,014	174,660
Derivative financial instruments, Financial liabilities	116,896	158,534
Total Fair Value [Member] | Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans, net	22,999,446	22,562,577
Deposits	29,036,525	29,482,628
Derivative financial instruments, Financial liabilities	1,621	2,089
Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	1,117,111	1,514,625
Available for sale securities	5,636,676	5,161,491
Held to maturity securities	2,231,335	2,435,663
Loans, net	23,148,561	22,980,565
Loans held for sale	30,760	21,525
Derivative financial instruments, Financial assets	71,083	73,840
Deposits	29,046,612	29,492,851
Federal funds purchased	110,300	300
Securities sold under agreements to repurchase	534,627	638,715
FHLB short-term borrowings	400,000
Long-term debt	210,620	210,544
Derivative financial instruments, Financial liabilities	$ 118,517	$ 160,623