Fair Value - Quantitative Information about Significant Unobservable Inputs Used in Fair Value Measurements (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investment securities - available-for-sale	$ 8,750,604	$ 7,382,066
Pooled trust preferred securities | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of adjusted specific issuer evaluation recoveries	0.00%
Percentage of adjusted specific issuer evaluation defaults	0.00%
Pooled trust preferred securities | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of adjusted specific issuer evaluation recoveries	100.00%
Percentage of adjusted specific issuer evaluation defaults	100.00%
Pooled trust preferred securities | Median
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of adjusted specific issuer evaluation recoveries	25.00%
Percentage of adjusted specific issuer evaluation defaults	50.00%
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 4,329	2,634
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 56,279	$ 16,308
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Minimum | Discount for type of property, age of appraisal, and current status | Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.14	0.14
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Minimum | Discount for type of property, age of appraisal, and current status | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.06	0.06
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Maximum | Discount for type of property, age of appraisal, and current status | Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.15	0.15
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Maximum | Discount for type of property, age of appraisal, and current status | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.10	0.10
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Weighted Average | Discount for type of property, age of appraisal, and current status | Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.14	0.14
Significant Unobservable Inputs (Level 3) | Collateral Dependent Loans | Weighted Average | Discount for type of property, age of appraisal, and current status | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.08	0.08
Significant Unobservable Inputs (Level 3) | Foreclosed Assets | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,678
Significant Unobservable Inputs (Level 3) | Foreclosed Assets | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 100
Significant Unobservable Inputs (Level 3) | Foreclosed Assets | Discount for type of property, age of appraisal, and current status | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.14
Significant Unobservable Inputs (Level 3) | Foreclosed Assets | Discount for type of property, age of appraisal, and current status | Residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investment securities - available-for-sale	$ 9,665	$ 9,496
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Constant prepayment rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.0000	0.0000
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Minimum | Expected asset recoveries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.000	0.000
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Minimum | Additional asset defaults
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.055	0.057
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Maximum | Expected asset recoveries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.462	0.460
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Maximum | Additional asset defaults
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.084	0.085
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Weighted Average | Expected asset recoveries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.141	0.141
Significant Unobservable Inputs (Level 3) | Pooled trust preferred securities | Weighted Average | Additional asset defaults
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.064	0.065