Loans and Leases (Details 2) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	$ 92,353	$ 79,333
Loans held for investment, net	18,846,872	17,957,713
Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	18,754,519
Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	20,824
Loans held for investment, net	7,972,747	7,918,141
Mortgages [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	7,951,923
Mortgages [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	18,346
Loans held for investment, net	4,202,687	4,824,298
Mortgages [Member] | Commercial Real Estate [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	4,184,341
Mortgages [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	2,478
Loans held for investment, net	3,770,060	3,093,843
Mortgages [Member] | Residential Real Estate [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	3,767,582
Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	364
Loans held for investment, net	2,737,802	2,233,656
Real Estate Construction [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	2,737,438
Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	364
Loans held for investment, net	1,082,368	912,583
Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,082,004
Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	0
Loans held for investment, net	1,655,434	1,321,073
Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,655,434
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	70,672
Loans held for investment, net	7,695,496	7,404,595
Commercial Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	7,624,824
Commercial Portfolio Segment [Member] | Asset Based [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	30,162
Loans held for investment, net	3,748,407	3,305,421
Commercial Portfolio Segment [Member] | Asset Based [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	3,718,245
Commercial Portfolio Segment [Member] | Venture Capital Loans [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	12,916
Loans held for investment, net	2,179,422	2,038,748
Commercial Portfolio Segment [Member] | Venture Capital Loans [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	2,166,506
Commercial Portfolio Segment [Member] | Other Commercial [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	27,594
Loans held for investment, net	1,767,667	2,060,426
Commercial Portfolio Segment [Member] | Other Commercial [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,740,073
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual	493
Loans held for investment, net	440,827	401,321
Consumer Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	440,334
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		79,333
Loans held for investment, net	$ 18,846,872	17,957,713
Non Purchased Credit Impaired Loans and Leases | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		17,878,380
Non Purchased Credit Impaired Loans and Leases | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		17,845
Loans held for investment, net		7,918,141
Non Purchased Credit Impaired Loans and Leases | Mortgages [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		7,900,296
Non Purchased Credit Impaired Loans and Leases | Mortgages [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		15,321
Loans held for investment, net		4,824,298
Non Purchased Credit Impaired Loans and Leases | Mortgages [Member] | Commercial Real Estate [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		4,808,977
Non Purchased Credit Impaired Loans and Leases | Mortgages [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		2,524
Loans held for investment, net		3,093,843
Non Purchased Credit Impaired Loans and Leases | Mortgages [Member] | Residential Real Estate [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		3,091,319
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		442
Loans held for investment, net		2,233,656
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		2,233,214
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		442
Loans held for investment, net		912,583
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		912,141
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		0
Loans held for investment, net		1,321,073
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		1,321,073
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		60,003
Loans held for investment, net		7,404,595
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		7,344,592
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Asset Based [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		32,324
Loans held for investment, net		3,305,421
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Asset Based [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		3,273,097
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Venture Capital Loans [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		20,299
Loans held for investment, net		2,038,748
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Venture Capital Loans [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		2,018,449
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Other Commercial [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		7,380
Loans held for investment, net		2,060,426
Non Purchased Credit Impaired Loans and Leases | Commercial Portfolio Segment [Member] | Other Commercial [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		2,053,046
Non Purchased Credit Impaired Loans and Leases | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Nonaccrual		1,043
Loans held for investment, net		401,321
Non Purchased Credit Impaired Loans and Leases | Consumer Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net		$ 400,278