Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	$ 1,415,025	$ 1,426,279
Deposits	15,338,557	15,569,763
Federal funds purchased and securities sold under repurchase agreements	393,215	405,745
Other borrowings	482,027	483,230
Subordinated notes	123,537	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	606,261	975,543
Securities held to maturity	1,415,025	1,426,279
Deposits	15,338,557	15,569,763
Federal funds purchased and securities sold under repurchase agreements	393,215	405,745
Other borrowings	482,027	483,230
Subordinated notes	123,537	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	606,261	975,543
Securities held to maturity	1,333,014	1,355,504
Deposits	15,320,852	15,553,417
Federal funds purchased and securities sold under repurchase agreements	393,215	405,745
Other borrowings	482,024	483,226
Subordinated notes	110,625	108,125
Junior subordinated debt securities	47,011	48,856
Level 3 [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI	12,914,945	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	$ 12,809,237	$ 12,762,505