Loans and Leases Held for Investment and Credit Quality - Amortized Cost Basis of Collateral-Dependent Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	$ 7,229,003	$ 6,854,154
Collateral Dependent Loans, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	29,532	36,137
Collateral Dependent Loans, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	3,205	371
Collateral Dependent Loans, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Unguaranteed Portion, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	10,324	20,639
Unguaranteed Portion, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	712	371
Unguaranteed Portion, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Unguaranteed Portion
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	1,430	443
Commercial & Industrial | Collateral Dependent Loans, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	10,753	19,108
Commercial & Industrial | Collateral Dependent Loans, Real Estate | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	7,731	2,730
Commercial & Industrial | Collateral Dependent Loans, Real Estate | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	3,022	16,378
Commercial & Industrial | Collateral Dependent Loans, Real Estate | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable		0
Commercial & Industrial | Collateral Dependent Loans, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	1,126	371
Commercial & Industrial | Collateral Dependent Loans, Business Assets | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	1,126	0
Commercial & Industrial | Collateral Dependent Loans, Business Assets | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Collateral Dependent Loans, Business Assets | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable		371
Commercial & Industrial | Collateral Dependent Loans, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Collateral Dependent Loans, Other | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Collateral Dependent Loans, Other | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Collateral Dependent Loans, Other | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable		0
Commercial & Industrial | Unguaranteed Portion, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	1,931	13,997
Commercial & Industrial | Unguaranteed Portion, Real Estate | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	1,704	414
Commercial & Industrial | Unguaranteed Portion, Real Estate | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	227	13,583
Commercial & Industrial | Unguaranteed Portion, Real Estate | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable		0
Commercial & Industrial | Unguaranteed Portion, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	295	371
Commercial & Industrial | Unguaranteed Portion, Business Assets | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	295	0
Commercial & Industrial | Unguaranteed Portion, Business Assets | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Unguaranteed Portion, Business Assets | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable		371
Commercial & Industrial | Unguaranteed Portion, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Unguaranteed Portion, Other | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Unguaranteed Portion, Other | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial & Industrial | Unguaranteed Portion, Other | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable		0
Commercial & Industrial | Unguaranteed Portion
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	1,257	291
Commercial & Industrial | Unguaranteed Portion | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	1,257	0
Commercial & Industrial | Unguaranteed Portion | Energy & Infrastructure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	0	0
Commercial & Industrial | Unguaranteed Portion | Specialty Lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses		291
Commercial Real Estate | Collateral Dependent Loans, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	17,036	15,286
Commercial Real Estate | Collateral Dependent Loans, Real Estate | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	17,036	15,286
Commercial Real Estate | Collateral Dependent Loans, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	2,079	0
Commercial Real Estate | Collateral Dependent Loans, Business Assets | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	2,079	0
Commercial Real Estate | Collateral Dependent Loans, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Real Estate | Collateral Dependent Loans, Other | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Real Estate | Unguaranteed Portion, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	8,191	6,440
Commercial Real Estate | Unguaranteed Portion, Real Estate | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	8,191	6,440
Commercial Real Estate | Unguaranteed Portion, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	417	0
Commercial Real Estate | Unguaranteed Portion, Business Assets | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	417	0
Commercial Real Estate | Unguaranteed Portion, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Real Estate | Unguaranteed Portion, Other | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Real Estate | Unguaranteed Portion
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	173	152
Commercial Real Estate | Unguaranteed Portion | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	173	152
Commercial Land | Collateral Dependent Loans, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	1,743	1,743
Commercial Land | Collateral Dependent Loans, Real Estate | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	1,743	1,743
Commercial Land | Collateral Dependent Loans, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Collateral Dependent Loans, Business Assets | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Collateral Dependent Loans, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Collateral Dependent Loans, Other | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Unguaranteed Portion, Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	202	202
Commercial Land | Unguaranteed Portion, Real Estate | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	202	202
Commercial Land | Unguaranteed Portion, Business Assets
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Unguaranteed Portion, Business Assets | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Unguaranteed Portion, Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Unguaranteed Portion, Other | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases receivable	0	0
Commercial Land | Unguaranteed Portion
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	0	0
Commercial Land | Unguaranteed Portion | Small Business Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Credit Losses	$ 0	$ 0