Fair Value Measurements (Assets and Liabilities) (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	$ 2,072,337	$ 2,057,851
Equity securities	1,256	1,325
Derivative assets	79,170	66,464
Derivative Liability	60,686	62,472
Foreclosed assets	8,578	8,731
Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	260,165	196,329
Equity securities	1,256	1,325
Derivative assets	0	0
Derivative Liability	0	0
Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	1,812,172	1,861,522
Equity securities	0	0
Derivative assets	79,231	65,903
Derivative Liability	60,644	61,412
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Equity securities	0	0
Derivative assets	0	0
Derivative Liability	0	0
Mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	1,670,464	1,708,831
Mortgage-backed securities | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Mortgage-backed securities | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	1,670,464	1,708,831
Mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	44,936	46,797
Asset-backed securities | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Asset-backed securities | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	44,936	46,797
Asset-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
State and municipal obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	63,846	69,707
State and municipal obligations | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
State and municipal obligations | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	63,846	69,707
State and municipal obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Corporate obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	32,926	36,187
Corporate obligations | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Corporate obligations | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	32,926	36,187
Corporate obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	2,072,337	2,057,851
Equity securities	1,256	1,325
Derivative assets	79,231	65,903
Assets, fair value	2,152,824	2,125,079
Derivative Liability	60,644	61,412
Measured on a Recurring Basis | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	260,165	196,329
Equity securities	1,256	1,325
Derivative assets	0	0
Assets, fair value	261,421	197,654
Derivative Liability	0	0
Measured on a Recurring Basis | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	1,812,172	1,861,522
Equity securities	0	0
Derivative assets	79,231	65,903
Assets, fair value	1,891,403	1,927,425
Derivative Liability	60,644	61,412
Measured on a Recurring Basis | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Equity securities	0	0
Derivative assets	0	0
Assets, fair value	0	0
Derivative Liability	0	0
Measured on a Recurring Basis | U.S. Treasury obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	260,165	196,329
Measured on a Recurring Basis | U.S. Treasury obligations | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	260,165	196,329
Measured on a Recurring Basis | U.S. Treasury obligations | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | U.S. Treasury obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | Mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	1,670,464	1,708,831
Measured on a Recurring Basis | Mortgage-backed securities | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | Mortgage-backed securities | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	1,670,464	1,708,831
Measured on a Recurring Basis | Mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	44,936	46,797
Measured on a Recurring Basis | Asset-backed securities | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | Asset-backed securities | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	44,936	46,797
Measured on a Recurring Basis | Asset-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | State and municipal obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	63,846	69,707
Measured on a Recurring Basis | State and municipal obligations | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | State and municipal obligations | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	63,846	69,707
Measured on a Recurring Basis | State and municipal obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | Corporate obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	32,926	36,187
Measured on a Recurring Basis | Corporate obligations | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Recurring Basis | Corporate obligations | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	32,926	36,187
Measured on a Recurring Basis | Corporate obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities, at fair value	0	0
Measured on a Non-Recurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	24,751	26,968
Loans measured for impairment based on the fair value of the underlying collateral	16,173	18,237
Foreclosed assets	8,578	8,731
Measured on a Non-Recurring Basis | Quoted Prices in Active  Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Loans measured for impairment based on the fair value of the underlying collateral	0	0
Foreclosed assets	0	0
Measured on a Non-Recurring Basis | Significant Other Observable  Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Loans measured for impairment based on the fair value of the underlying collateral	0	0
Foreclosed assets	0	0
Measured on a Non-Recurring Basis | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	24,751	26,968
Loans measured for impairment based on the fair value of the underlying collateral	16,173	18,237
Foreclosed assets	$ 8,578	$ 8,731