Loans - Summary of Aging of Recorded Investment in Past Due Portfolio Loans by Portfolio Class and Category (Details) - Non-Covered Loans - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 52,110
Current	5,405,407
Loans, including unearned loan fees	5,457,517	$ 5,314,337
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	34,389
Current	2,434,624
Loans, including unearned loan fees	2,469,013
CRE - investor owned
Financing Receivable, Past Due [Line Items]
Total Past Due	5,434
Current	1,322,380
Loans, including unearned loan fees	1,327,814
CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Total Past Due	5,052
Current	715,491
Loans, including unearned loan fees	720,543
Construction and land development
Financing Receivable, Past Due [Line Items]
Total Past Due	95
Current	469,532
Loans, including unearned loan fees	469,627
Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	6,606
Current	340,152
Loans, including unearned loan fees	346,758
Consumer and other
Financing Receivable, Past Due [Line Items]
Total Past Due	534
Current	123,228
Loans, including unearned loan fees	123,762
Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	36,442
Financial Asset, 30 to 89 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	24,898
Financial Asset, 30 to 89 Days Past Due [Member] | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Total Past Due	1,996
Financial Asset, 30 to 89 Days Past Due [Member] | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Total Past Due	3,870
Financial Asset, 30 to 89 Days Past Due [Member] | Construction and land development
Financing Receivable, Past Due [Line Items]
Total Past Due	95
Financial Asset, 30 to 89 Days Past Due [Member] | Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	5,124
Financial Asset, 30 to 89 Days Past Due [Member] | Consumer and other
Financing Receivable, Past Due [Line Items]
Total Past Due	459
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	15,668
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	9,491
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Total Past Due	3,438
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Total Past Due	1,182
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction and land development
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	1,482
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer and other
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 75