Loans and Leases Held for Investment - Nonaccrual and Performing Loans and Leases Held for Investment (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025
Financing Receivable, Impaired [Line Items]
Nonaccrual	$ 185,734	$ 159,168	$ 213,480
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	24,435,218	24,831,721
Loans and leases HFI	24,780,347	25,032,679	24,126,527
Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Nonaccrual	154,237	154,676	198,948
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	13,340,828	13,581,261
Loans and leases HFI	13,506,898	13,750,787	13,492,658
Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Nonaccrual	0	0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	1,718,717	1,921,087
Loans and leases HFI	1,892,329	1,947,627	2,861,038
Commercial
Financing Receivable, Impaired [Line Items]
Nonaccrual	30,434	3,135	13,540
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	9,030,497	8,974,976
Loans and leases HFI	9,032,987	8,977,206	7,378,799
Consumer
Financing Receivable, Impaired [Line Items]
Nonaccrual	1,063	1,357	992
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	345,176	354,397
Loans and leases HFI	348,133	357,059	$ 394,032
Performing
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	24,594,613	24,873,511
Performing | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	13,352,661	13,596,111
Performing | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	1,892,329	1,947,627
Performing | Commercial
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	9,002,553	8,974,071
Performing | Consumer
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	347,070	355,702
Venture Capital Loans | Commercial
Financing Receivable, Impaired [Line Items]
Nonaccrual	28,792	625
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	2,321,666	2,222,097
Loans and leases HFI	2,322,261	2,222,097
Venture Capital Loans | Performing | Commercial
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	2,293,469	2,221,472
Other Commercial | Commercial
Financing Receivable, Impaired [Line Items]
Nonaccrual	1,642	2,510
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	3,500,002	3,803,011
Loans and leases HFI	3,501,388	3,804,099
Other Commercial | Performing | Commercial
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	3,499,746	3,801,589
Asset Based | Commercial
Financing Receivable, Impaired [Line Items]
Nonaccrual	0	0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	3,208,829	2,949,868
Loans and leases HFI	3,209,338	2,951,010
Asset Based | Performing | Commercial
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	3,209,338	2,951,010
Commercial Real Estate Construction Loan Receivable | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Nonaccrual	0	0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	331,650	379,387
Loans and leases HFI	364,575	379,387
Commercial Real Estate Construction Loan Receivable | Performing | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	364,575	379,387
Residential Real Estate Construction Financing Receivable | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Nonaccrual	0	0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	1,387,067	1,541,700
Loans and leases HFI	1,527,754	1,568,240
Residential Real Estate Construction Financing Receivable | Performing | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	1,527,754	1,568,240
Commercial | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Nonaccrual	87,548	93,334
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	4,041,500	4,257,633
Loans and leases HFI	4,093,386	4,314,637
Commercial | Performing | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	4,005,838	4,221,303
Other Residential Real Estate | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Nonaccrual	53,489	57,984
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	3,379,605	3,269,634
Loans and leases HFI	3,458,410	3,346,733
Other Residential Real Estate | Performing | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	3,404,921	3,288,749
Multifamily | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Nonaccrual	13,200	3,358
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	5,919,723	6,053,994
Loans and leases HFI	5,955,102	6,089,417
Multifamily | Performing | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current	$ 5,941,902	$ 6,086,059