Loans and Leases (Details 3) - Non Purchased Credit Impaired Loans and Leases - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 14,306,961	$ 14,289,209	$ 12,017,881
Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	384,698	391,754
Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	13,922,263	13,897,455
Consumer Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	110,622	120,849	93,675
Consumer Portfolio Segment | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,385	2,500
Consumer Portfolio Segment | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	109,237	118,349
Commercial Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,990,569	7,952,577	6,007,067
Commercial Portfolio Segment | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	297,480	276,225
Commercial Portfolio Segment | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,693,089	7,676,352
Commercial Portfolio Segment | Cash Flow
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,165,814	3,062,268
Commercial Portfolio Segment | Cash Flow | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	209,108	183,726
Commercial Portfolio Segment | Cash Flow | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	2,956,706	2,878,542
Commercial Portfolio Segment | Asset Based
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	2,588,916	2,547,533
Commercial Portfolio Segment | Asset Based | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	22,236	19,340
Commercial Portfolio Segment | Asset Based | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	2,566,680	2,528,193
Commercial Portfolio Segment | Venture Capital Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,502,611	1,452,427
Commercial Portfolio Segment | Venture Capital Loans | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	14,889	19,105
Commercial Portfolio Segment | Venture Capital Loans | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,487,722	1,433,322
Commercial Portfolio Segment | Equipment Finance Commercial Financing Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	733,228	890,349
Commercial Portfolio Segment | Equipment Finance Commercial Financing Receivable | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	51,247	54,054
Commercial Portfolio Segment | Equipment Finance Commercial Financing Receivable | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	681,981	836,295
Real Estate Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	575,473	527,720	328,709
Real Estate Construction | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,940	1,966
Real Estate Construction | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	573,533	525,754
Real Estate Construction | Commercial Real Estate Construction Loan Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	305,529	343,360
Real Estate Construction | Commercial Real Estate Construction Loan Receivable | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	558	571
Real Estate Construction | Commercial Real Estate Construction Loan Receivable | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	304,971	342,789
Real Estate Construction | Residential Real Estate Construction Financing Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	269,944	184,360
Real Estate Construction | Residential Real Estate Construction Financing Receivable | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,382	1,395
Real Estate Construction | Residential Real Estate Construction Financing Receivable | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	268,562	182,965
Mortgage Loans on Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	5,630,297	5,688,063	$ 5,588,430
Mortgage Loans on Real Estate | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	83,893	111,063
Mortgage Loans on Real Estate | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	5,546,404	5,577,000
Mortgage Loans on Real Estate | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,552,961	4,551,958
Mortgage Loans on Real Estate | Commercial Real Estate | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	65,532	98,436
Mortgage Loans on Real Estate | Commercial Real Estate | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,487,429	4,453,522
Mortgage Loans on Real Estate | Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,077,336	1,136,105
Mortgage Loans on Real Estate | Residential Real Estate | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	18,361	12,627
Mortgage Loans on Real Estate | Residential Real Estate | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 1,058,975	$ 1,123,478