Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	$ 1,156,985	$ 342,537
Deposits	14,425,180	15,087,160
Federal funds purchased and securities sold under repurchase agreements	544,068	238,577
Other borrowings	223,172	91,025
Subordinated notes	123,207	123,042
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	489,735	2,266,829
Securities held to maturity	1,156,985	342,537
Deposits	14,425,180	15,087,160
Federal funds purchased and securities sold under repurchase agreements	544,068	238,577
Other borrowings	223,172	91,025
Subordinated notes	123,207	123,042
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	489,735	2,266,829
Securities held to maturity	1,065,828	353,511
Deposits	14,396,980	15,084,440
Federal funds purchased and securities sold under repurchase agreements	544,068	238,577
Other borrowings	223,165	91,022
Subordinated notes	113,750	128,438
Junior subordinated debt securities	47,629	49,485
Level 3 [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI and PPP loans	11,475,812	10,181,708
Level 3 [Member] | Estimate Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net LHFI and PPP loans	$ 11,194,672	$ 10,123,379