Fair Value Measurements - Summary of Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Securities available-for-sale	$ 1,135,317	$ 721,369
Total Fair Value
Assets
State tax credits held for sale	39,046	39,169
Obligations of U.S. Government-sponsored enterprises
Assets
Securities available-for-sale	10,046	98,498
Obligations of states and political subdivisions
Assets
Securities available-for-sale	213,024	26,810
Residential mortgage-backed securities
Assets
Securities available-for-sale	902,021	586,136
US Treasury Bill Securities [Member]
Assets
Securities available-for-sale	10,226	9,925
Recurring basis \| Total Fair Value
Assets
Securities available-for-sale	1,135,317	721,369
Other Investments		121
Derivative financial instruments	11,055	3,023
Assets, Fair Value Disclosure	1,146,372	724,513
Liabilities
Derivative financial instruments	14,747	3,023
Total liabilities	14,747	3,023
Recurring basis \| Obligations of U.S. Government-sponsored enterprises \| Total Fair Value
Assets
Securities available-for-sale	10,046	98,498
Recurring basis \| Obligations of states and political subdivisions \| Total Fair Value
Assets
Securities available-for-sale	213,024	26,810
Recurring basis \| Residential mortgage-backed securities \| Total Fair Value
Assets
Securities available-for-sale	902,021	586,136
Recurring basis \| US Treasury Bill Securities [Member] \| Total Fair Value
Assets
Securities available-for-sale	10,226	9,925
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Securities available-for-sale	0	0
Other Investments		121
Derivative financial instruments	0	0
Assets, Fair Value Disclosure	0	121
Liabilities
Derivative financial instruments	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) \| Residential 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 \| Significant Other Observable Inputs (Level 2)
Assets
Securities available-for-sale	1,135,317	721,369
Other Investments		0
Derivative financial instruments	11,055	3,023
Assets, Fair Value Disclosure	1,146,372	724,392
Liabilities
Derivative financial instruments	14,747	3,023
Total liabilities	14,747	3,023
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available-for-sale	10,046	98,498
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Obligations of states and political subdivisions
Assets
Securities available-for-sale	213,024	26,810
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Residential mortgage-backed securities
Assets
Securities available-for-sale	902,021	586,136
Recurring basis \| Significant Other Observable Inputs (Level 2) \| US Treasury Bill Securities [Member]
Assets
Securities available-for-sale	10,226	9,925
Recurring basis \| Significant Unobservable Inputs (Level 3)
Assets
Securities available-for-sale	0	0
Other Investments		0
Derivative financial instruments	0	0
Assets, Fair Value Disclosure	0	0
Liabilities
Derivative financial instruments	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) \| Residential 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

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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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