Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Held to maturity securities	$ 2,570,622	$ 2,684,779
Loans held for sale	26,051	13,269
Derivative financial instruments, Financial assets	91,647	84,458
Derivative financial instruments, Financial liabilities	93,407	87,567
Total Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	1,082,437	1,188,284
Available for sale securities	4,965,214	4,915,195
Held to maturity securities	2,347,957	2,485,918
Loans, net	23,060,921	23,186,259
Loans held for sale	27,354	26,124
Derivative financial instruments, Financial assets	91,000	90,712
Deposits	29,185,869	29,679,228
Federal funds purchased	150,350	350
Securities sold under agreements to repurchase	563,609	454,479
FHLB short-term borrowings	650,000	700,000
Long-term debt	192,949	196,182
Derivative financial instruments, Financial liabilities	226,442	207,138
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	1,082,437	1,188,284
Federal funds purchased	150,350	350
Securities sold under agreements to repurchase	563,609	454,479
FHLB short-term borrowings	650,000	700,000
Total Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Available for sale securities	4,965,214	4,915,195
Held to maturity securities	2,347,957	2,485,918
Loans, net	40,099	15,882
Loans held for sale	27,354	26,124
Derivative financial instruments, Financial assets	91,000	90,712
Long-term debt	192,949	196,182
Derivative financial instruments, Financial liabilities	223,889	205,796
Total Fair Value [Member] | Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans, net	23,020,822	23,170,377
Deposits	29,185,869	29,679,228
Derivative financial instruments, Financial liabilities	2,553	1,342
Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	1,082,437	1,188,284
Available for sale securities	4,965,214	4,915,195
Held to maturity securities	2,570,622	2,684,779
Loans, net	23,595,468	23,614,010
Loans held for sale	27,354	26,124
Derivative financial instruments, Financial assets	91,000	90,712
Deposits	29,200,718	29,690,059
Federal funds purchased	150,350	350
Securities sold under agreements to repurchase	563,609	454,479
FHLB short-term borrowings	650,000	700,000
Long-term debt	236,393	236,317
Derivative financial instruments, Financial liabilities	$ 226,442	$ 207,138