Disclosures about Fair Value of Assets and Liabilities - Fair Value Measurements of Assets and Liabilities Recognized on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,669,634	$ 1,134,025
U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	118,588	19,715
State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,119,123	837,843
Federal agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	75,525	147,453
Federal agency mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	237,705	118,799
Private labeled mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	32,937	0
Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	85,756	10,215
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,669,634	1,134,025
Recurring Basis | U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	118,588	19,715
Recurring Basis | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,119,123	837,843
Recurring Basis | Federal agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	75,525	147,453
Recurring Basis | Federal agency mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	237,705	118,799
Recurring Basis | Private labeled mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	32,937
Recurring Basis | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	85,756	10,215
Recurring Basis | Interest rate swap agreements asset
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	19,391	35,388
Recurring Basis | Forward sale commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	666	1,045
Recurring Basis | Interest rate swap agreements liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	(24,044)	(43,631)
Recurring Basis | Commitments to originate loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	(333)
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Federal agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Federal agency mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Private labeled mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate swap agreements asset
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Forward sale commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate swap agreements liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0	0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commitments to originate loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0
Recurring Basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,669,634	1,134,025
Recurring Basis | Significant Other Observable Inputs (Level 2) | U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	118,588	19,715
Recurring Basis | Significant Other Observable Inputs (Level 2) | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,119,123	837,843
Recurring Basis | Significant Other Observable Inputs (Level 2) | Federal agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	75,525	147,453
Recurring Basis | Significant Other Observable Inputs (Level 2) | Federal agency mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	237,705	118,799
Recurring Basis | Significant Other Observable Inputs (Level 2) | Private labeled mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	32,937
Recurring Basis | Significant Other Observable Inputs (Level 2) | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	85,756	10,215
Recurring Basis | Significant Other Observable Inputs (Level 2) | Interest rate swap agreements asset
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	19,391	35,388
Recurring Basis | Significant Other Observable Inputs (Level 2) | Forward sale commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	666	1,045
Recurring Basis | Significant Other Observable Inputs (Level 2) | Interest rate swap agreements liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	(24,044)	(43,631)
Recurring Basis | Significant Other Observable Inputs (Level 2) | Commitments to originate loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	(333)
Recurring Basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Federal agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Federal agency mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Private labeled mortgage-backed pools
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value
Recurring Basis | Significant Unobservable Inputs (Level 3) | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Interest rate swap agreements asset
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Forward sale commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0	0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Interest rate swap agreements liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	0	$ 0
Recurring Basis | Significant Unobservable Inputs (Level 3) | Commitments to originate loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, fair value	$ 0