Loans and Leases (Details 3) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	$ 15,455,954	$ 14,478,254
Non Purchased Credit Impaired Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	15,347,530	14,289,209
Non Purchased Credit Impaired Loans and Leases [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	409,645	391,754
Non Purchased Credit Impaired Loans and Leases [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	14,937,885	13,897,455
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	5,617,956	5,688,063
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	117,181	111,063
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	5,500,775	5,577,000
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	4,353,633	4,551,958
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Commercial Real Estate [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	99,641	98,436
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Commercial Real Estate [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	4,253,992	4,453,522
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	1,264,323	1,136,105
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Residential Real Estate [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	17,540	12,627
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Residential Real Estate [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	1,246,783	1,123,478
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	962,839	527,720
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	773	1,966
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	962,066	525,754
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	578,838	343,360
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	409	571
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	578,429	342,789
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	384,001	184,360
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	364	1,395
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	383,637	182,965
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	8,391,560	7,952,577
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	291,267	276,225
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	8,100,293	7,676,352
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Cash Flow [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	3,107,392	3,062,268
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Cash Flow [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	177,661	183,726
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Cash Flow [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	2,929,731	2,878,542
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Asset Based [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	2,609,045	2,547,533
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Asset Based [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	28,112	19,340
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Asset Based [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	2,580,933	2,528,193
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Venture Capital Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	1,983,156	1,452,427
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Venture Capital Loans [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	52,646	19,105
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Venture Capital Loans [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	1,930,510	1,433,322
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Equipment Finance Commercial Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	691,967	890,349
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Equipment Finance Commercial Financing Receivable [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	32,848	54,054
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Equipment Finance Commercial Financing Receivable [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	659,119	836,295
Non Purchased Credit Impaired Loans and Leases [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	375,175	120,849
Non Purchased Credit Impaired Loans and Leases [Member] | Consumer Portfolio Segment [Member] | Classified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	424	2,500
Non Purchased Credit Impaired Loans and Leases [Member] | Consumer Portfolio Segment [Member] | Nonclassified [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment, net	$ 374,751	$ 118,349