Loans and Leases (Aging Of The Outstanding Loans and Leases By Class Excluding Loans Impaired At Acquisition Date) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 11,493,458	$ 11,263,074
Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	608,556	550,568
Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	7,591,745	7,552,948
Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	262,293	244,875
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,072,414	1,988,934
Commercial | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	603,737	571,916
Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	354,713	353,833
Non-PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	71,450	57,321
60-89 Days Past Due	15,735	19,548
90 Days or Greater	25,068	24,598
Total	112,253	101,467
Current	17,732,161	17,481,500
Loans and leases, not acquired in a transfer accounted for as debt securities	17,844,414	17,582,967
Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	2,709	1,796
60-89 Days Past Due	712	621
90 Days or Greater	1,044	385
Total	4,465	2,802
Current	604,091	547,766
Loans and leases, not acquired in a transfer accounted for as debt securities	608,556	550,568
Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	22,635	11,367
60-89 Days Past Due	5,920	4,782
90 Days or Greater	8,445	8,061
Total	37,000	24,210
Current	7,554,745	7,528,738
Loans and leases, not acquired in a transfer accounted for as debt securities	7,591,745	7,552,948
Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	583	206
60-89 Days Past Due	58	70
90 Days or Greater	196	102
Total	837	378
Current	261,456	244,497
Loans and leases, not acquired in a transfer accounted for as debt securities	262,293	244,875
Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	6,290	2,843
60-89 Days Past Due	1,724	1,545
90 Days or Greater	570	378
Total	8,584	4,766
Current	2,063,830	1,984,168
Loans and leases, not acquired in a transfer accounted for as debt securities	2,072,414	1,988,934
Non-PCI Loans | Commercial | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	476	1,631
60-89 Days Past Due	11	8
90 Days or Greater	0	2
Total	487	1,641
Current	603,250	570,275
Loans and leases, not acquired in a transfer accounted for as debt securities	603,737	571,916
Non-PCI Loans | Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	380	146
60-89 Days Past Due	65	1,966
90 Days or Greater	133	0
Total	578	2,112
Current	354,135	351,721
Loans and leases, not acquired in a transfer accounted for as debt securities	354,713	353,833
Non-PCI Loans | Noncommerical
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	38,377	39,332
60-89 Days Past Due	7,245	10,556
90 Days or Greater	14,680	15,670
Current	6,290,654	6,254,335
Loans and leases, not acquired in a transfer accounted for as debt securities	6,350,956	6,319,893
Non-PCI Loans | Noncommerical | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	21,844	23,288
60-89 Days Past Due	2,896	6,018
90 Days or Greater	9,356	8,955
Total	34,096	38,261
Current	2,490,453	2,482,281
Loans and leases, not acquired in a transfer accounted for as debt securities	2,524,549	2,520,542
Non-PCI Loans | Noncommerical | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	10,288	11,097
60-89 Days Past Due	2,794	2,433
90 Days or Greater	4,296	5,463
Total	17,378	18,993
Current	2,510,879	2,542,807
Loans and leases, not acquired in a transfer accounted for as debt securities	2,528,257	2,561,800
Non-PCI Loans | Noncommerical | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	2,009	370
60-89 Days Past Due	0	486
90 Days or Greater	0	147
Total	2,009	1,003
Current	168,199	119,094
Loans and leases, not acquired in a transfer accounted for as debt securities	170,208	120,097
Non-PCI Loans | Noncommerical | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	4,236	4,577
60-89 Days Past Due	1,555	1,619
90 Days or Greater	1,028	1,105
Total	6,819	7,301
Current	1,121,123	1,110,153
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 1,127,942	$ 1,117,454