Loans and Leases - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($) contract	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($) contract	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	$ 125,396,000	$ 89,742,000	$ 125,396,000	$ 89,742,000		$ 103,778,000
Allowance for Loan and Lease Losses, Period Increase (Decrease)			3,100,000
Provision for credit losses	8,000,000	3,000,000	66,500,000	9,000,000
Gross loans and leases held for investment	21,969,789,000		21,969,789,000			28,726,016,000
Loans and Leases Receivable, Allowance	222,297,000	189,327,000	222,297,000	189,327,000	$ 219,234,000	200,732,000	$ 188,705,000	$ 200,564,000
Loans held for investment, net	21,920,946,000	$ 27,660,041,000	21,920,946,000	$ 27,660,041,000		28,609,129,000
Number of loans | contract		16		39
Pre-Modification Outstanding Recorded Investment		$ 5,769,000		$ 8,906,000
Real Estate Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	119,794,000	75,823,000	119,794,000	75,823,000		98,402,000
Provision for credit losses	8,944,000	(4,065,000)	87,891,000	16,548,000
Gross loans and leases held for investment	14,056,774,000		14,056,774,000			15,762,351,000
Loans and Leases Receivable, Allowance	136,530,000	79,452,000	136,530,000	79,452,000	132,808,000	87,309,000	85,896,000	98,624,000
Loans held for investment, net	14,034,491,000	$ 15,164,765,000	14,034,491,000	$ 15,164,765,000		15,730,324,000
Real Estate Mortgage | Other Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	88,329,000		88,329,000			55,893,000
Loans held for investment, net	5,228,524,000		5,228,524,000			6,275,628,000
Number of loans | contract		10		10
Pre-Modification Outstanding Recorded Investment		$ 3,596,000		$ 3,599,000
Real Estate Mortgage | Other Residential Real Estate | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans		1		1
Financing Receivable, Troubled Debt Restructuring, Subsequent Default		$ 97,000		$ 97,000
Financing Receivable, Excluding Accrued Interest, Modified, Increase (Decrease) from Modification	8,700,000		8,700,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	5,395,000	13,552,000	5,395,000	13,552,000		5,210,000
Provision for credit losses	(1,411,000)	(3,284,000)	(11,272,000)	1,248,000
Gross loans and leases held for investment	4,756,921,000		4,756,921,000			8,297,182,000
Loans and Leases Receivable, Allowance	36,674,000	51,221,000	36,674,000	51,221,000	$ 37,221,000	52,849,000	$ 54,031,000	$ 48,718,000
Loans held for investment, net	4,754,430,000	$ 8,271,182,000	4,754,430,000	$ 8,271,182,000		8,281,962,000
Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	20,500,000		$ 20,500,000
Credit Concentration Risk | Nonaccrual Loans And Leases Benchmark | Fair Value, Concentration of Risk, All Financial Instruments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of nonaccrual loans and leases			16.00%
Nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable, 90 or more days past due	77,300,000		$ 77,300,000			70,900,000
Receivable, 30-89 days past due	11,900,000		11,900,000			6,800,000
Financing receivable, nonaccrual status, current	36,100,000		36,100,000			26,000,000
Other Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	3,031,000		3,031,000			4,345,000
Loans held for investment, net	1,002,377,000		1,002,377,000			1,108,451,000
Number of loans | contract		2		21
Pre-Modification Outstanding Recorded Investment		$ 102,000		$ 1,233,000
Venture Capital Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	2,001,000		2,001,000			0
Loans held for investment, net	1,464,160,000		1,464,160,000			2,033,302,000
Number of loans | contract		2		4
Pre-Modification Outstanding Recorded Investment		$ 1,649,000		$ 3,330,000
Asset-based | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	363,000		363,000			865,000
Loans held for investment, net	$ 2,287,893,000		$ 2,287,893,000			$ 5,140,209,000