Loans and Leases (Details 1) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Delinquent loans in loan portfolio
30-89 Days Past Due	$ 45,000	$ 3,600
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	20,500	16,800
Loans held for investment, net	14,641,460	14,478,254
Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	51,209	10,622
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	20,505	17,508
Financing Receivable, Recorded Investment, Past Due	71,714	28,130
Current	14,432,866	14,261,079
Loans held for investment, net	14,504,580	14,289,209	$ 11,811,551
Mortgage Loans on Real Estate | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	5,842	7,338
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	16,140	13,980
Financing Receivable, Recorded Investment, Past Due	21,982	21,318
Current	5,541,398	5,666,745
Loans held for investment, net	5,563,380	5,688,063	5,410,431
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	5,400	3,947
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	14,244	13,075
Financing Receivable, Recorded Investment, Past Due	19,644	17,022
Current	4,446,762	4,534,936
Loans held for investment, net	4,466,406	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	442	3,391
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,896	905
Financing Receivable, Recorded Investment, Past Due	2,338	4,296
Current	1,094,636	1,131,809
Loans held for investment, net	1,096,974	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	696,233	527,720
Loans held for investment, net	696,233	527,720	348,739
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	414,466	343,360
Loans held for investment, net	414,466	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	281,767	184,360
Loans held for investment, net	281,767	184,360
Commercial Portfolio Segment | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	45,367	2,658
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	4,361	2,221
Financing Receivable, Recorded Investment, Past Due	49,728	4,879
Current	7,982,605	7,947,698
Loans held for investment, net	8,032,333	7,952,577	5,966,102
Commercial Portfolio Segment | Cash Flow | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	458	2,048
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,852	1,427
Financing Receivable, Recorded Investment, Past Due	2,310	3,475
Current	3,039,552	3,058,793
Loans held for investment, net	3,041,862	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	0	1
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Financing Receivable, Recorded Investment, Past Due	0	1
Current	2,682,264	2,547,532
Loans held for investment, net	2,682,264	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	3,548	250
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	700
Financing Receivable, Recorded Investment, Past Due	3,548	950
Current	1,657,719	1,451,477
Loans held for investment, net	1,661,267	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	41,361	359
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2,509	94
Financing Receivable, Recorded Investment, Past Due	43,870	453
Current	603,070	889,896
Loans held for investment, net	646,940	890,349
Consumer Portfolio Segment | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	0	626
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	4	1,307
Financing Receivable, Recorded Investment, Past Due	4	1,933
Current	212,630	118,916
Loans held for investment, net	$ 212,634	$ 120,849	$ 86,279