Loans and Leases - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($) contract	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($) contract	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	$ 104,886,000	$ 78,527,000	$ 104,886,000	$ 78,527,000		$ 103,778,000
Allowance for Loan and Lease Losses, Period Increase (Decrease)			9,200,000
Provision for credit losses	40,000,000	10,000,000	58,500,000	12,000,000
Gross loans and leases held for investment	22,311,292,000		22,311,292,000			28,726,016,000
Loans and Leases Receivable, Allowance	219,234,000	188,705,000	219,234,000	188,705,000	$ 210,055,000	200,732,000	$ 197,398,000	$ 200,564,000
Loans held for investment, net	22,258,210,000	$ 26,501,137,000	22,258,210,000	$ 26,501,137,000		28,609,129,000
Number of loans | contract		12		26
Pre-Modification Outstanding Recorded Investment		$ 3,613,000		$ 4,991,000
Real Estate Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	100,817,000	62,996,000	100,817,000	62,996,000		98,402,000
Provision for credit losses	(47,138,000)	1,092,000	(78,947,000)	12,483,000
Gross loans and leases held for investment	14,312,273,000		14,312,273,000			15,762,351,000
Loans and Leases Receivable, Allowance	132,808,000	85,896,000	132,808,000	85,896,000	109,483,000	87,309,000	87,228,000	98,624,000
Loans held for investment, net	14,288,042,000	$ 14,054,085,000	14,288,042,000	$ 14,054,085,000		15,730,324,000
Real Estate Mortgage | Other Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	63,626,000		63,626,000			55,893,000
Loans held for investment, net	5,373,178,000		5,373,178,000			6,275,628,000
Number of loans | contract		1		2
Pre-Modification Outstanding Recorded Investment		$ 208,000		$ 512,000
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		$ 104,000		$ 104,000
Financing Receivable, Excluding Accrued Interest, Modified, Increase (Decrease) from Modification	4,100,000		4,100,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	3,864,000	8,964,000	3,864,000	8,964,000		5,210,000
Provision for credit losses	(6,631,000)	4,904,000	(9,861,000)	(4,532,000)
Gross loans and leases held for investment	5,097,714,000		5,097,714,000			8,297,182,000
Loans and Leases Receivable, Allowance	37,221,000	54,031,000	37,221,000	54,031,000	$ 37,195,000	52,849,000	$ 57,056,000	$ 48,718,000
Loans held for investment, net	5,094,786,000	$ 8,476,806,000	5,094,786,000	$ 8,476,806,000		8,281,962,000
Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	24,900,000		$ 24,900,000
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			24.00%
Nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable, 90 or more days past due	62,300,000		$ 62,300,000			70,900,000
Receivable, 30-89 days past due	7,600,000		7,600,000			6,800,000
Financing receivable, nonaccrual status, current	35,000,000		35,000,000			26,000,000
Other Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | contract		2		2
Financing Receivable, Troubled Debt Restructuring, Subsequent Default		$ 110,000		$ 110,000
Other Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	3,479,000		3,479,000			4,345,000
Loans held for investment, net	1,014,212,000		1,014,212,000			1,108,451,000
Number of loans | contract		6		19
Pre-Modification Outstanding Recorded Investment		$ 57,000		$ 1,131,000
Venture Capital Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	0		0			0
Loans held for investment, net	1,723,476,000		1,723,476,000			2,033,302,000
Number of loans | contract		4		4
Pre-Modification Outstanding Recorded Investment		$ 3,330,000		$ 3,330,000
Asset-based | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	385,000		385,000			865,000
Loans held for investment, net	$ 2,357,098,000		$ 2,357,098,000			$ 5,140,209,000