Loans and Leases (Details 2) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 170,599	$ 129,019
Loans held for investment, net	15,455,954	14,478,254
Non Purchased Credit Impaired Loans and Leases [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	170,599	129,019
Loans held for investment, net	15,347,530	14,289,209
Non Purchased Credit Impaired Loans and Leases [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	15,176,931	14,160,190
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	69,335	57,277
Loans held for investment, net	5,617,956	5,688,063
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	5,548,621	5,630,786
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	62,454	52,363
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	4,291,179	4,499,595
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	6,881	4,914
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,257,442	1,131,191
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	364	372
Loans held for investment, net	962,839	527,720
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	962,475	527,348
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	578,838	343,360
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Residential Real Estate Construction Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	364	372
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	383,637	183,988
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	100,561	69,839
Loans held for investment, net	8,391,560	7,952,577
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	8,290,999	7,882,738
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Cash Flow [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	53,908	15,800
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	3,053,484	3,046,468
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Asset Based [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	2,118	2,505
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	2,606,927	2,545,028
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Equipment Finance Commercial Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	32,848	51,410
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	659,119	838,939
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member] | Venture Capital Loans [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	11,687	124
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] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	1,971,469	1,452,303
Non Purchased Credit Impaired Loans and Leases [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	339	1,531
Loans held for investment, net	375,175	120,849
Non Purchased Credit Impaired Loans and Leases [Member] | Consumer Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Loans held for investment, net	$ 374,836	$ 119,318