Allowance for Credit Losses - Collateral Dependent Loans by Class of Loan (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	$ 6,999,990	$ 7,225,860
Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	34,456	108,525
Blanket Lien
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	6,541	16,699
Investment/Cash
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	10,473	689
Commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	2,690,528	2,791,947
Commercial | Commercial real estate | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	28,046	100,450
Commercial | Commercial real estate | Blanket Lien
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Commercial real estate | Investment/Cash
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Commercial real estate | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	1,513,523	1,559,552
Commercial | Commercial and industrial | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	259	1,040
Commercial | Commercial and industrial | Blanket Lien
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	4,905	15,080
Commercial | Commercial and industrial | Investment/Cash
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Commercial and industrial | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	10,473	0
Commercial | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	424,755	466,077
Commercial | Commercial construction | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	4,210	3,552
Commercial | Commercial construction | Blanket Lien
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Commercial construction | Investment/Cash
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Commercial construction | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Business banking
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	1,135,693	1,160,067
Commercial | Business banking | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	910	3,085
Commercial | Business banking | Blanket Lien
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	1,636	1,619
Commercial | Business banking | Investment/Cash
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Commercial | Business banking | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	689
Consumer | Consumer real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	1,127,585	1,167,332
Consumer | Consumer real estate | Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	1,031	398
Consumer | Consumer real estate | Blanket Lien
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Consumer | Consumer real estate | Investment/Cash
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	0	0
Consumer | Consumer real estate | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans held for investment, outstanding balance	$ 0	$ 0