Loans and Leases (Details 2) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	$ 91,163	$ 92,353
Loans held for investment, net	19,083,377	18,846,872
Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	45,557	20,824
Loans held for investment, net	7,899,936	7,972,747
Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	315	364
Loans held for investment, net	3,360,281	2,737,802
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	44,902	70,672
Loans held for investment, net	7,502,905	7,695,496
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	389	493
Loans held for investment, net	320,255	440,827
Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	18,992,214	18,754,519
Performing Financing Receivable [Member] | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	7,854,379	7,951,923
Performing Financing Receivable [Member] | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	3,359,966	2,737,438
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	7,458,003	7,624,824
Performing Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	319,866	440,334
Asset Based [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	2,679	30,162
Loans held for investment, net	3,429,283	3,748,407
Asset Based [Member] | Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	3,426,604	3,718,245
Venture Capital Loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	1,980	12,916
Loans held for investment, net	1,698,508	2,179,422
Venture Capital Loans [Member] | Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,696,528	2,166,506
Other Commercial [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	40,243	27,594
Loans held for investment, net	2,375,114	1,767,667
Other Commercial [Member] | Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	2,334,871	1,740,073
Commercial Real Estate Construction Loan Receivable [Member] | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	315	364
Loans held for investment, net	1,117,121	1,082,368
Commercial Real Estate Construction Loan Receivable [Member] | Performing Financing Receivable [Member] | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,116,806	1,082,004
Residential Real Estate Construction Financing Receivable [Member] | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	0	0
Loans held for investment, net	2,243,160	1,655,434
Residential Real Estate Construction Financing Receivable [Member] | Performing Financing Receivable [Member] | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	2,243,160	1,655,434
Commercial Real Estate [Member] | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	43,731	18,346
Loans held for investment, net	4,096,671	4,202,687
Commercial Real Estate [Member] | Performing Financing Receivable [Member] | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	4,052,940	4,184,341
Residential Real Estate [Member] | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	1,826	2,478
Loans held for investment, net	3,803,265	3,770,060
Residential Real Estate [Member] | Performing Financing Receivable [Member] | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	$ 3,801,439	$ 3,767,582