Portfolio Loans - Summary of Recorded Investment by Risk Category of Portfolio Loans by Portfolio Class and Category (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total		$ 5,314,337
Loans, including unearned loan fees	$ 7,224,935	5,314,337
Non-Covered Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	7,241,074	5,316,953
Loans, including unearned loan fees		5,224,048
Non-Covered Loans | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,100,299	2,345,823
Non-Covered Loans | Commercial - investor owned
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,589,419	1,262,981
Non-Covered Loans | CRE - owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,498,408	678,522
Non-Covered Loans | Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total	546,686	449,380
Non-Covered Loans | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	319,179	355,192
Non-Covered Loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 187,083	134,941
Loans, including unearned loan fees		132,150
Pass (1-6) | Non-Covered Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, including unearned loan fees		4,954,405
Pass (1-6) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total		2,151,084
Pass (1-6) | Non-Covered Loans | Commercial - investor owned
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,242,569
Pass (1-6) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Total		643,276
Pass (1-6) | Non-Covered Loans | Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total		437,134
Pass (1-6) | Non-Covered Loans | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total		348,246
Pass (1-6) | Non-Covered Loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, including unearned loan fees		132,096
Watch (7) | Non-Covered Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, including unearned loan fees		187,656
Watch (7) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total		124,718
Watch (7) | Non-Covered Loans | Commercial - investor owned
Financing Receivable, Credit Quality Indicator [Line Items]
Total		17,572
Watch (7) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Total		28,773
Watch (7) | Non-Covered Loans | Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total		12,140
Watch (7) | Non-Covered Loans | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total		4,450
Watch (7) | Non-Covered Loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, including unearned loan fees		3
Classified (8 & 9) | Non-Covered Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, including unearned loan fees		81,987
Classified (8 & 9) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total		70,021
Classified (8 & 9) | Non-Covered Loans | Commercial - investor owned
Financing Receivable, Credit Quality Indicator [Line Items]
Total		2,840
Classified (8 & 9) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Total		6,473
Classified (8 & 9) | Non-Covered Loans | Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total		106
Classified (8 & 9) | Non-Covered Loans | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total		2,496
Classified (8 & 9) | Non-Covered Loans | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, including unearned loan fees		$ 51