Loans and Leases (Details 1) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Delinquent loans in loan portfolio
30-89 Days Past Due	$ 3,000	$ 3,600
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	15,900	16,800
Loans held for investment, net	15,455,954	14,478,254
Non Purchased Credit Impaired Loans and Leases [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	31,569	10,622
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	15,945	17,508
Financing Receivable, Recorded Investment, Past Due	47,514	28,130
Current	15,300,016	14,261,079
Loans held for investment, net	15,347,530	14,289,209
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	14,284	7,338
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	5,302	13,980
Financing Receivable, Recorded Investment, Past Due	19,586	21,318
Current	5,598,370	5,666,745
Loans held for investment, net	5,617,956	5,688,063
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Commercial Real Estate [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	8,590	3,947
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,303	13,075
Financing Receivable, Recorded Investment, Past Due	11,893	17,022
Current	4,341,740	4,534,936
Loans held for investment, net	4,353,633	4,551,958
Non Purchased Credit Impaired Loans and Leases [Member] | Mortgages [Member] | Residential Real Estate [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	5,694	3,391
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,999	905
Financing Receivable, Recorded Investment, Past Due	7,693	4,296
Current	1,256,630	1,131,809
Loans held for investment, net	1,264,323	1,136,105
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	364	0
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	364	0
Current	962,475	527,720
Loans held for investment, net	962,839	527,720
Non Purchased Credit Impaired Loans and Leases [Member] | Real Estate Construction [Member] | Commercial Real Estate Construction Loan Receivable [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	0	0
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	0	0
Current	578,838	343,360
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]
Delinquent loans in loan portfolio
30-89 Days Past Due	364	0
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	364	0
Current	383,637	184,360
Loans held for investment, net	384,001	184,360
Non Purchased Credit Impaired Loans and Leases [Member] | Commercial Portfolio Segment [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	16,697	2,658
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	10,643	2,221
Financing Receivable, Recorded Investment, Past Due	27,340	4,879
Current	8,364,220	7,947,698
Loans held for investment, net	8,391,560	7,952,577
Non Purchased Credit Impaired Loans and Leases [Member] | Consumer Portfolio Segment [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	224	626
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	1,307
Financing Receivable, Recorded Investment, Past Due	224	1,933
Current	374,951	118,916
Loans held for investment, net	375,175	120,849
Non Purchased Credit Impaired Loans and Leases [Member] | Cash Flow [Member] | Commercial Portfolio Segment [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	191	2,048
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,821	1,427
Financing Receivable, Recorded Investment, Past Due	2,012	3,475
Current	3,105,380	3,058,793
Loans held for investment, net	3,107,392	3,062,268
Non Purchased Credit Impaired Loans and Leases [Member] | Asset Based [Member] | Commercial Portfolio Segment [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	1,500	1
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2	0
Financing Receivable, Recorded Investment, Past Due	1,502	1
Current	2,607,543	2,547,532
Loans held for investment, net	2,609,045	2,547,533
Non Purchased Credit Impaired Loans and Leases [Member] | Venture Capital Loans [Member] | Commercial Portfolio Segment [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	13,589	250
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	5,769	700
Financing Receivable, Recorded Investment, Past Due	19,358	950
Current	1,963,798	1,451,477
Loans held for investment, net	1,983,156	1,452,427
Non Purchased Credit Impaired Loans and Leases [Member] | Equipment Finance Commercial Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Delinquent loans in loan portfolio
30-89 Days Past Due	1,417	359
Loan Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,051	94
Financing Receivable, Recorded Investment, Past Due	4,468	453
Current	687,499	889,896
Loans held for investment, net	$ 691,967	$ 890,349