Portfolio Loans - Summary of Portfolio Loans by Category (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, including unearned loan fees	$ 5,314,337	$ 4,350,001
Non-Covered Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	5,226,664	4,305,626
Unearned loan fees, net	(2,616)	(2,026)
Loans, including unearned loan fees	5,224,048	4,303,600
Non-Covered Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	2,345,823	2,121,008
Non-Covered Loans | CRE - investor owned
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	1,262,981	843,728
Non-Covered Loans | CRE - owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	678,522	604,498
Non-Covered Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	449,380	330,097
Non-Covered Loans | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	355,192	298,944
Non-Covered Loans | Total real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	2,746,075	2,077,267
Non-Covered Loans | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	134,766	107,351
Loans, including unearned loan fees	$ 132,150	$ 105,325