Loans (Financing Receivables Credit Quality Indicators) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Originated Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	$ 13,648,325	$ 12,493,812	$ 12,071,759
Originated Loans | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,521,955	5,175,201	5,039,320
Originated Loans | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,089,533	2,117,118	2,119,734
Originated Loans | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	619,569	537,766	467,112
Originated Loans | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	461,642	370,179	339,936
Originated Loans | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	8,692,699	8,200,264	7,966,102
Originated Loans | Grade One | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	71,992	52,676	42,653
Originated Loans | Grade One | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	787	683	695
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	13,262	4,451	8,929
Originated Loans | Grade One | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	86,041	58,488	52,277
Originated Loans | Grade Two | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	314,520	186,278	214,307
Originated Loans | Grade Two | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	842	3,454	3,523
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	52,397	14,959	12,525
Originated Loans | Grade Two | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	367,759	204,691	230,355
Originated Loans | Grade Three | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,312,560	1,340,100	1,164,149
Originated Loans | Grade Three | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	316,917	294,281	285,652
Originated Loans | Grade Three | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	64,270	46,074	36,953
Originated Loans | Grade Three | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	52,886	71,908	58,157
Originated Loans | Grade Three | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,746,633	1,752,363	1,544,911
Originated Loans | Grade Four | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,611,381	3,413,446	3,458,074
Originated Loans | Grade Four | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,709,902	1,745,470	1,761,138
Originated Loans | Grade Four | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	547,558	490,757	420,721
Originated Loans | Grade Four | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	338,014	277,277	258,880
Originated Loans | Grade Four | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	6,206,855	5,926,950	5,898,813
Originated Loans | Grade Five | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	114,683	139,083	119,252
Originated Loans | Grade Five | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	23,351	29,990	29,410
Originated Loans | Grade Five | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	6,651	257	9,359
Originated Loans | Grade Five | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,894	1,389	1,233
Originated Loans | Grade Five | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	147,579	170,719	159,254
Originated Loans | Grade Six | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	93,559	43,618	40,885
Originated Loans | Grade Six | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	37,734	43,240	39,316
Originated Loans | Grade Six | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,090	0	79
Originated Loans | Grade Six | Commercial Leases Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,189	195	212
Originated Loans | Grade Six | Commercial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	134,572	87,053	80,492
Originated Loans | Grade Seven | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,260	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	3,260	0	0
Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,914,964	2,479,180	2,745,104
Acquired Loans | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	274,552	449,254	551,489
Acquired Loans | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	497,690	630,674	710,495
Acquired Loans | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	6,172	6,971	10,260
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	778,414	1,086,899	1,272,244
Acquired Loans | Grade One | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	1,054	1,076	0
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	1,054	1,076	0
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	15,624	20,891	14,464
Acquired Loans | Grade Three | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	26,411	24,867	26,216
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	42,035	45,758	40,680
Acquired Loans | Grade Four | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	220,011	376,129	492,667
Acquired Loans | Grade Four | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	442,588	532,447	592,969
Acquired Loans | Grade Four | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,459	6,286	10,260
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	668,058	914,862	1,095,896
Acquired Loans | Grade Five | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	15,102	23,268	19,672
Acquired Loans | Grade Five | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,528	28,382	44,570
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	20,630	52,335	64,242
Acquired Loans | Grade Six | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	22,761	27,890	24,686
Acquired Loans | Grade Six | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	23,163	44,978	46,740
Acquired Loans | Grade Six | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	713	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	46,637	72,868	71,426
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	225,065	331,122	394,417
Covered Loans | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	38,787	48,837	56,076
Covered Loans | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	94,531	153,508	192,746
Covered Loans | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,859	9,262	13,497
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	139,177	211,607	262,319
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	1,125	1,347	1,373
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	1,125	1,347	1,373
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	35,534	36,406	40,902
Covered Loans | Grade Four | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	62,605	86,779	101,360
Covered Loans | Grade Four | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	817	823	686
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	98,956	124,008	142,948
Covered Loans | Grade Five | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	167	1,245
Covered Loans | Grade Five | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	629	3,401	3,908
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	629	3,568	5,153
Covered Loans | Grade Six | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,128	10,917	12,556
Covered Loans | Grade Six | Real Estate Loan
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	31,297	63,328	87,478
Covered Loans | Grade Six | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	5,042	8,248	12,659
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	38,467	82,493	112,693
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	0
Covered Loans | Grade Seven | Construction Loans
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	191	152
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	$ 152