Fair Value Measurement - Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		$ 1,339,821	$ 1,299,014
Derivative assets	[1]	9,439	0
Derivative liabilities	[1]	21,282	21,046
US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		298,998
State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		770,283	964,852
Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		12,991	8,704
Residential MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[2]	247,233	315,027
Commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[2]	10,316	10,431
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments		5,235	5,235
Total asset fair value measurements		1,432,755	1,386,555
Total liability fair value measurements		21,282	21,217
Fair Value, Recurring | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		298,998
Fair Value, Recurring | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		770,283	964,852
Fair Value, Recurring | Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		12,991	8,704
Fair Value, Recurring | Residential MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	247,233	315,027
Fair Value, Recurring | Commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	10,316	10,431
Fair Value, Recurring | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		87,699	82,306
Derivative liabilities		21,282	21,217
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments		5,235	5,235
Total asset fair value measurements		304,233	5,235
Total liability fair value measurements		0	0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		298,998
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		0	0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		0	0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	0	0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	0	0
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments		0	0
Total asset fair value measurements		1,128,522	1,381,320
Total liability fair value measurements		21,282	21,217
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		770,283	964,852
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		12,991	8,704
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Residential MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	247,233	315,027
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	10,316	10,431
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		87,699	82,306
Derivative liabilities		21,282	21,217
Fair Value, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments		0	0
Total asset fair value measurements		0	0
Total liability fair value measurements		0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Residential MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[3]	0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0	0
Derivative liabilities		0	0
Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreclosed assets		42	167
Total asset fair value measurements		7,581	7,982
Fair Value, Nonrecurring | Collateral-dependent loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent loans	[4]	7,539	7,815
Fair Value, Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreclosed assets		0	0
Total asset fair value measurements		0	0
Fair Value, Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Collateral-dependent loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent loans	[4]	0	0
Fair Value, Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreclosed assets		0	0
Total asset fair value measurements		0	0
Fair Value, Nonrecurring | Significant Other Observable Inputs (Level 2) | Collateral-dependent loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent loans	[4]	0	0
Fair Value, Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreclosed assets		42	167
Total asset fair value measurements		7,581	7,982
Fair Value, Nonrecurring | Significant Unobservable Inputs (Level 3) | Collateral-dependent loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent loans	[4]	$ 7,539	$ 7,815

[1] Net derivative assets are included in other assets and net derivative liabilities are included in other liabilities on the consolidated balance sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and our credit risk. We had $9.4 million credit exposure related to interest rate swaps with financial institutions and none related to interest rate swaps with customers at June 30, 2023. We had no credit exposure related to interest rate swaps with financial institutions and none related to interest rate swaps with customers at December 31, 2022. The credit risk associated with customer transactions is partially mitigated as these are generally secured by the non-cash collateral securing the underlying transaction being hedged.

[2] All MBS are issued and/or guaranteed by U.S. government agencies or U.S. GSEs.

[3] All MBS are issued and/or guaranteed by U.S. government agencies or U.S. GSEs.

[4] Consists of individually evaluated loans. Loans for which the fair value of the collateral and commercial real estate fair value of the properties is less than cost basis are presented net of allowance. Losses on these loans represent charge-offs which are netted against the allowance for loan losses.