Loans (Financing Receivables Credit Quality Indicators) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Originated Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	$ 13,355,912	$ 12,493,812	$ 11,467,193
Originated Loans | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,471,363	5,175,201	4,857,615
Originated Loans | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,138,372	2,117,118	2,098,018
Originated Loans | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	586,895	537,766	409,866
Originated Loans | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	436,702	370,179	319,795
Originated Loans | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	8,633,332	8,200,264	7,685,294
Originated Loans | Grade One | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	65,856	52,676	33,855
Originated Loans | Grade One | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	807	683	0
Originated Loans | Grade One | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	678	0
Originated Loans | Grade One | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	14,688	4,451	9,408
Originated Loans | Grade One | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	81,351	58,488	43,263
Originated Loans | Grade Two | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	206,384	186,278	134,682
Originated Loans | Grade Two | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,166	3,454	3,610
Originated Loans | Grade Two | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Originated Loans | Grade Two | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	29,564	14,959	10,971
Originated Loans | Grade Two | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	237,114	204,691	149,263
Originated Loans | Grade Three | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,417,295	1,340,100	1,100,807
Originated Loans | Grade Three | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	367,457	294,281	290,652
Originated Loans | Grade Three | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	55,889	46,074	36,954
Originated Loans | Grade Three | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	65,664	71,908	55,648
Originated Loans | Grade Three | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,906,305	1,752,363	1,484,061
Originated Loans | Grade Four | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,567,387	3,413,446	3,439,210
Originated Loans | Grade Four | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,715,998	1,745,470	1,725,808
Originated Loans | Grade Four | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	529,517	490,757	371,488
Originated Loans | Grade Four | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	321,268	277,277	236,324
Originated Loans | Grade Four | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	6,134,170	5,926,950	5,772,830
Originated Loans | Grade Five | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	98,137	139,083	100,776
Originated Loans | Grade Five | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	25,466	29,990	29,382
Originated Loans | Grade Five | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	360	257	0
Originated Loans | Grade Five | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,956	1,389	7,092
Originated Loans | Grade Five | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	126,919	170,719	137,250
Originated Loans | Grade Six | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	112,661	43,618	48,285
Originated Loans | Grade Six | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	27,478	43,240	48,566
Originated Loans | Grade Six | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,129	0	1,424
Originated Loans | Grade Six | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,562	195	352
Originated Loans | Grade Six | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	143,830	87,053	98,627
Originated Loans | Grade Seven | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,643	0	0
Originated Loans | Grade Seven | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Originated Loans | Grade Seven | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Originated Loans | Grade Seven | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Originated Loans | Grade Seven | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,643	0	0
Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,095,684	2,479,180	3,023,787
Acquired Loans | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	337,423	449,254	660,261
Acquired Loans | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	533,945	630,674	783,743
Acquired Loans | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	6,230	6,971	13,899
Acquired Loans | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	877,598	1,086,899	1,457,903
Acquired Loans | Grade One | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,061	1,076	700
Acquired Loans | Grade One | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade One | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade One | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade One | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,061	1,076	700
Acquired Loans | Grade Two | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Two | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Two | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Two | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Two | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Three | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	17,338	20,891	35,608
Acquired Loans | Grade Three | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	27,190	24,867	26,652
Acquired Loans | Grade Three | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Three | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Three | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	44,528	45,758	62,260
Acquired Loans | Grade Four | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	289,027	376,129	553,293
Acquired Loans | Grade Four | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	453,830	532,447	651,011
Acquired Loans | Grade Four | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,536	6,286	13,899
Acquired Loans | Grade Four | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Four | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	748,393	914,862	1,218,203
Acquired Loans | Grade Five | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	13,283	23,268	41,213
Acquired Loans | Grade Five | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	16,815	28,382	50,267
Acquired Loans | Grade Five | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	685	0
Acquired Loans | Grade Five | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Five | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	30,098	52,335	91,480
Acquired Loans | Grade Six | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	16,714	27,890	29,447
Acquired Loans | Grade Six | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	36,110	44,978	55,813
Acquired Loans | Grade Six | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	694	0	0
Acquired Loans | Grade Six | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Six | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	53,518	72,868	85,260
Acquired Loans | Grade Seven | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Seven | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Seven | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Seven | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Acquired Loans | Grade Seven | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	241,694	331,122	434,666
Covered Loans | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	38,137	48,837	56,423
Covered Loans | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	101,809	153,508	217,256
Covered Loans | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,875	9,262	19,101
Covered Loans | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	145,821	211,607	292,780
Covered Loans | Grade One | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade One | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade One | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade One | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade One | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Two | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,129	1,347	1,015
Covered Loans | Grade Two | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Two | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Two | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Two | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,129	1,347	1,015
Covered Loans | Grade Three | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Three | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Three | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Three | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Three | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Four | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	33,992	36,406	38,892
Covered Loans | Grade Four | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	65,906	86,779	104,455
Covered Loans | Grade Four | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	817	823	707
Covered Loans | Grade Four | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Four | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	100,715	124,008	144,054
Covered Loans | Grade Five | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	167	999
Covered Loans | Grade Five | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	625	3,401	3,984
Covered Loans | Grade Five | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Five | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Five | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	625	3,568	4,983
Covered Loans | Grade Six | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,016	10,917	15,517
Covered Loans | Grade Six | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	35,278	63,328	108,637
Covered Loans | Grade Six | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,058	8,248	18,045
Covered Loans | Grade Six | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Six | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	43,352	82,493	142,199
Covered Loans | Grade Seven | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Seven | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	180
Covered Loans | Grade Seven | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	191	349
Covered Loans | Grade Seven | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0	0
Covered Loans | Grade Seven | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	$ 0	$ 191	$ 529