Portfolio Loans - Summary of Aging of Recorded Investment in Past Due Portfolio Loans by Portfolio Class and Category (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 9,017,642	$ 7,224,935
Non-Covered Loans
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,026,780	7,241,074
Financing Receivable, Covered, after Allowance for Credit Loss	9,017,642	7,224,935
Non-Covered Loans | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	41,639	13,529
Non-Covered Loans | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	15,763	29,044
Non-Covered Loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	57,402	42,573
Non-Covered Loans | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,960,240	7,182,362
Non-Covered Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,396,590	3,100,299
Financing Receivable, Covered, after Allowance for Credit Loss	3,392,375	3,088,995
Non-Covered Loans | Commercial and industrial | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	24,447	8,652
Non-Covered Loans | Commercial and industrial | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	14,158	12,928
Non-Covered Loans | Commercial and industrial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	38,605	21,580
Non-Covered Loans | Commercial and industrial | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,353,770	3,067,415
Non-Covered Loans | Commercial - investor owned
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,141,143	1,589,419
Financing Receivable, Covered, after Allowance for Credit Loss	2,141,143	1,589,419
Non-Covered Loans | Commercial - investor owned | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,880	734
Non-Covered Loans | Commercial - investor owned | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	9,301
Non-Covered Loans | Commercial - investor owned | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,880	10,035
Non-Covered Loans | Commercial - investor owned | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,137,263	1,579,384
Non-Covered Loans | CRE - owner occupied
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,035,785	1,498,408
Financing Receivable, Covered, after Allowance for Credit Loss	2,035,785	1,498,408
Non-Covered Loans | CRE - owner occupied | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,070	328
Non-Covered Loans | CRE - owner occupied | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	289	4,647
Non-Covered Loans | CRE - owner occupied | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,359	4,975
Non-Covered Loans | CRE - owner occupied | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,025,426	1,493,433
Non-Covered Loans | Construction and land development
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	734,073	546,686
Financing Receivable, Covered, after Allowance for Credit Loss	734,073	546,686
Non-Covered Loans | Construction and land development | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	24	13
Non-Covered Loans | Construction and land development | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Non-Covered Loans | Construction and land development | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	24	13
Non-Covered Loans | Construction and land development | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	734,049	546,673
Non-Covered Loans | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	454,052	319,179
Financing Receivable, Covered, after Allowance for Credit Loss	454,052	319,179
Non-Covered Loans | Residential real estate | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,181	2,071
Non-Covered Loans | Residential real estate | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,305	2,118
Non-Covered Loans | Residential real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,486	4,189
Non-Covered Loans | Residential real estate | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	449,566	314,990
Non-Covered Loans | Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	265,137	187,083
Financing Receivable, Covered, after Allowance for Credit Loss	260,214	182,248
Non-Covered Loans | Other | Financial Asset, 30-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	37	1,731
Non-Covered Loans | Other | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	11	50
Non-Covered Loans | Other | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	48	1,781
Non-Covered Loans | Other | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 260,166	$ 180,467