Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	$ 1,358,358	$ 1,426,279
Net LHFI	12,942,182	12,811,157
Deposits	15,240,935	15,569,763
Federal funds purchased and securities sold under repurchase agreements	365,643	405,745
Other borrowings	443,458	483,230
Subordinated notes	123,647	123,482
Junior subordinated debt securities	61,856	61,856
Level 2 [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and short-term investments	815,436	975,343
Securities held to maturity	1,358,358	1,426,279
Deposits	15,240,935	15,569,763
Federal funds purchased and securities sold under repurchase agreements	365,643	405,745
Other borrowings	443,458	483,230
Subordinated notes	123,647	123,482
Junior subordinated debt securities	61,856	61,856
Level 2 [Member] | Estimate Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and short-term investments	815,436	975,343
Securities held to maturity	1,316,167	1,355,504
Deposits	15,234,983	15,553,417
Federal funds purchased and securities sold under repurchase agreements	365,643	405,745
Other borrowings	443,458	483,226
Subordinated notes	119,063	108,125
Junior subordinated debt securities	48,248	48,856
Level 3 [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI	12,942,182	12,811,157
Level 3 [Member] | Estimate Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI	$ 13,025,566	$ 12,762,505