Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	$ 1,440,527	$ 1,553,905
Derivative assets	$ 15,239	$ 41,099
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Interest Receivable and Other Assets	Interest Receivable and Other Assets
Derivative liabilities	$ 13,420	$ 39,176
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities	Other Liabilities
U.S. Treasury [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	$ 1,390,782	$ 1,498,045
U.S. Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	9,683	11,770
Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	13,908	14,795
States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	9,951	10,010
Asset backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	9,381	12,512
Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	6,822	6,773
Level 1 Inputs [Member] | U.S. Treasury [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1,390,782	1,498,045
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	15,239	41,099
Derivative liabilities	13,420	39,176
Level 2 Inputs [Member] | U.S. Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	9,683	11,770
Level 2 Inputs [Member] | Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	13,908	14,795
Level 2 Inputs [Member] | States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	9,801	9,830
Level 2 Inputs [Member] | Asset backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	9,381	12,512
Level 2 Inputs [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	6,822	6,773
Level 3 Inputs [Member] | States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	$ 150	$ 180