Fair Value Measurements - Summary of Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets
Securities available for sale	$ 998,104	$ 1,135,317
Estimate of Fair Value Measurement [Member]
Assets
State tax credits held for sale	44,164	39,046
Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	10,241	10,046
Obligations of states and political subdivisions
Assets
Securities available for sale	254,278	213,024
Agency mortgage-backed securities
Assets
Securities available for sale	720,991	902,021
US Treasury Bill Securities [Member]
Assets
Securities available for sale	10,566	10,226
Corporate Debt Securities [Member]
Assets
Securities available for sale	2,028
Recurring basis \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	998,104	1,135,317
Derivatives	35,728	11,055
Total assets	1,033,832	1,146,372
Liabilities
Derivatives	46,828	14,747
Total liabilities	46,828	14,747
Recurring basis \| Obligations of U.S. Government-sponsored enterprises \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	10,241	10,046
Recurring basis \| Obligations of states and political subdivisions \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	254,278	213,024
Recurring basis \| Agency mortgage-backed securities \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	720,991	902,021
Recurring basis \| US Treasury Bill Securities [Member] \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	10,566	10,226
Recurring basis \| Corporate Debt Securities [Member] \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	2,028
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Securities available for sale	0	0
Derivatives	0	0
Total assets	0	0
Liabilities
Derivatives	0	0
Total liabilities	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Obligations of states and political subdivisions
Assets
Securities available for sale	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Agency mortgage-backed securities
Assets
Securities available for sale	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| US Treasury Bill Securities [Member]
Assets
Securities available for sale	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate Debt Securities [Member]
Assets
Securities available for sale	0
Recurring basis \| Significant Other Observable Inputs (Level 2)
Assets
Securities available for sale	998,104	1,135,317
Derivatives	35,728	11,055
Total assets	1,033,832	1,146,372
Liabilities
Derivatives	46,828	14,747
Total liabilities	46,828	14,747
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	10,241	10,046
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Obligations of states and political subdivisions
Assets
Securities available for sale	254,278	213,024
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Agency mortgage-backed securities
Assets
Securities available for sale	720,991	902,021
Recurring basis \| Significant Other Observable Inputs (Level 2) \| US Treasury Bill Securities [Member]
Assets
Securities available for sale	10,566	10,226
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Corporate Debt Securities [Member]
Assets
Securities available for sale	2,028
Recurring basis \| Significant Unobservable Inputs (Level 3)
Assets
Securities available for sale	0	0
Derivatives	0	0
Total assets	0	0
Liabilities
Derivatives	0	0
Total liabilities	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Obligations of states and political subdivisions
Assets
Securities available for sale	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Agency mortgage-backed securities
Assets
Securities available for sale	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| US Treasury Bill Securities [Member]
Assets
Securities available for sale	$ 0	$ 0

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value of financial and nonfinancial obligations.

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