Portfolio Loans - Summary of Portfolio Loans by Category (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees		$ 5,314,337
Non-Covered Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	$ 7,241,074	5,316,953
Unearned loan fees, net	(16,139)	(2,616)
Loans, including unearned loan fees	7,224,935	5,314,337
Non-Covered Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	3,100,299	2,345,823
Non-Covered Loans | Commercial - investor owned
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	1,589,419	1,262,981
Non-Covered Loans | CRE - owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	1,498,408	678,522
Non-Covered Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	546,686	449,380
Non-Covered Loans | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	319,179	355,192
Non-Covered Loans | Total real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	3,953,692	2,820,855
Non-Covered Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	$ 187,083	134,941
Non-Covered Loans | Residential Real Estate Financing Receivable, Including Loans Previously Reported as PCI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees		366,261
Non-Covered Loans | Construction and Land Development Financing Receivable, Including Loans Previously Reported as PCI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees		457,273
Non-Covered Loans | Commercial Real Estate Owner Occupied Financing Receivable, Including Loans Previously Reported as PCI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees		697,437
Non-Covered Loans | Commercial Real Estate Investor Owned Financing Receivable, Including Loans Previously Reported as PCI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees		1,299,884
Non-Covered Loans | Commercial and Industrial Portfolio Segment, Including Loans Previously Reported as PCI
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees		$ 2,361,157