Loans and Leases (Details 1) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Delinquent loans in loan portfolio
30-89 Days Past Due	$ 13,700	$ 3,600
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	13,500	16,800
Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	31,440	10,622
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	16,058	17,508
Financing Receivable, Recorded Investment, Past Due	47,498	28,130
Current	14,259,463	14,261,079
Loans held for investment, net	14,306,961	14,289,209	$ 12,017,881
Mortgage Loans on Real Estate | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	18,842	7,338
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	11,197	13,980
Financing Receivable, Recorded Investment, Past Due	30,039	21,318
Current	5,600,258	5,666,745
Loans held for investment, net	5,630,297	5,688,063	5,588,430
Mortgage Loans on Real Estate | Commercial Real Estate | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	16,655	3,947
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	10,638	13,075
Financing Receivable, Recorded Investment, Past Due	27,293	17,022
Current	4,525,668	4,534,936
Loans held for investment, net	4,552,961	4,551,958
Mortgage Loans on Real Estate | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	2,187	3,391
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	559	905
Financing Receivable, Recorded Investment, Past Due	2,746	4,296
Current	1,074,590	1,131,809
Loans held for investment, net	1,077,336	1,136,105
Real Estate Construction | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	0	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	0	0
Current	575,473	527,720
Loans held for investment, net	575,473	527,720	328,709
Real Estate Construction | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	0	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	0	0
Current	305,529	343,360
Loans held for investment, net	305,529	343,360
Real Estate Construction | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	0	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	0	0
Current	269,944	184,360
Loans held for investment, net	269,944	184,360
Commercial Portfolio Segment | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	12,568	2,658
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	4,153	2,221
Financing Receivable, Recorded Investment, Past Due	16,721	4,879
Current	7,973,848	7,947,698
Loans held for investment, net	7,990,569	7,952,577	6,007,067
Commercial Portfolio Segment | Cash Flow | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	766	2,048
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2,013	1,427
Financing Receivable, Recorded Investment, Past Due	2,779	3,475
Current	3,163,035	3,058,793
Loans held for investment, net	3,165,814	3,062,268
Commercial Portfolio Segment | Asset Based | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	4	1
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	4	1
Current	2,588,912	2,547,532
Loans held for investment, net	2,588,916	2,547,533
Commercial Portfolio Segment | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	9,554	250
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	700
Financing Receivable, Recorded Investment, Past Due	9,554	950
Current	1,493,057	1,451,477
Loans held for investment, net	1,502,611	1,452,427
Commercial Portfolio Segment | Equipment Finance Commercial Financing Receivable | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	2,244	359
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2,140	94
Financing Receivable, Recorded Investment, Past Due	4,384	453
Current	728,844	889,896
Loans held for investment, net	733,228	890,349
Consumer Portfolio Segment | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	30	626
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	708	1,307
Financing Receivable, Recorded Investment, Past Due	738	1,933
Current	109,884	118,916
Loans held for investment, net	$ 110,622	$ 120,849	$ 93,675