Loans - Summary of Aging of Recorded Investment in Past Due Portfolio Loans by Portfolio Class and Category (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 9,056,073	$ 9,017,642
Non-Covered Loans
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,064,414	9,026,780
Loans, including unearned loan fees	9,056,073	9,017,642
Non-Covered Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,400,574	3,396,590
Loans, including unearned loan fees	3,398,723	3,392,375
Non-Covered Loans | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,184,126	2,141,143
Loans, including unearned loan fees	2,184,126	2,141,143
Non-Covered Loans | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,094,012	2,035,785
Loans, including unearned loan fees	2,094,012	2,035,785
Non-Covered Loans | Construction and land development
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	702,630	734,073
Loans, including unearned loan fees	702,630	734,073
Non-Covered Loans | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	432,639	454,052
Loans, including unearned loan fees	432,639	454,052
Non-Covered Loans | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	250,433	265,137
Loans, including unearned loan fees	243,943	260,214
Total Past Due | Non-Covered Loans
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	24,419	57,402
Total Past Due | Non-Covered Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,290	38,605
Total Past Due | Non-Covered Loans | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,026	3,880
Total Past Due | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,390	10,359
Total Past Due | Non-Covered Loans | Construction and land development
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,680	24
Total Past Due | Non-Covered Loans | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,988	4,486
Total Past Due | Non-Covered Loans | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	45	48
30-89 Days Past Due | Non-Covered Loans
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	15,488	41,639
30-89 Days Past Due | Non-Covered Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,086	24,447
30-89 Days Past Due | Non-Covered Loans | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,461	3,880
30-89 Days Past Due | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,692	10,070
30-89 Days Past Due | Non-Covered Loans | Construction and land development
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,680	24
30-89 Days Past Due | Non-Covered Loans | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,534	3,181
30-89 Days Past Due | Non-Covered Loans | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	35	37
90 or More Days Past Due | Non-Covered Loans
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,931	15,763
90 or More Days Past Due | Non-Covered Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,204	14,158
90 or More Days Past Due | Non-Covered Loans | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,565	0
90 or More Days Past Due | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,698	289
90 or More Days Past Due | Non-Covered Loans | Construction and land development
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
90 or More Days Past Due | Non-Covered Loans | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	454	1,305
90 or More Days Past Due | Non-Covered Loans | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	10	11
Current | Non-Covered Loans
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,031,654	8,960,240
Current | Non-Covered Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,390,433	3,353,770
Current | Non-Covered Loans | CRE - investor owned
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,181,100	2,137,263
Current | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,087,622	2,025,426
Current | Non-Covered Loans | Construction and land development
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	699,950	734,049
Current | Non-Covered Loans | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	428,651	449,566
Current | Non-Covered Loans | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 243,898	$ 260,166