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, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 59,418
Current	7,229,363
Loans, including unearned loan fees	7,288,781	$ 7,224,935
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	43,067
Current	3,036,576
Loans, including unearned loan fees	3,079,643
CRE - investor owned
Financing Receivable, Past Due [Line Items]
Total Past Due	7,468
Current	1,661,747
Loans, including unearned loan fees	1,669,215
CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Total Past Due	4,299
Current	1,513,456
Loans, including unearned loan fees	1,517,755
Construction and land development
Financing Receivable, Past Due [Line Items]
Total Past Due	400
Current	510,101
Loans, including unearned loan fees	510,501
Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	3,461
Current	299,586
Loans, including unearned loan fees	303,047
Other
Financing Receivable, Past Due [Line Items]
Total Past Due	723
Current	207,897
Loans, including unearned loan fees	208,620
Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	30,313
Financial Asset, 30 to 89 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	25,976
Financial Asset, 30 to 89 Days Past Due [Member] | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Total Past Due	768
Financial Asset, 30 to 89 Days Past Due [Member] | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Total Past Due	312
Financial Asset, 30 to 89 Days Past Due [Member] | Construction and land development
Financing Receivable, Past Due [Line Items]
Total Past Due	400
Financial Asset, 30 to 89 Days Past Due [Member] | Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	2,371
Financial Asset, 30 to 89 Days Past Due [Member] | Other
Financing Receivable, Past Due [Line Items]
Total Past Due	486
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	29,105
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	17,091
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Total Past Due	6,700
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Total Past Due	3,987
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	1,090
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Other
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 237