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	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 17,582,967	$ 12,104,298
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	11,263,074	8,499,348
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	550,568	319,847
Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	7,552,948	6,362,490
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	244,875	178,754
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	1,988,934	1,081,158
Commercial | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	571,916	381,763
Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	353,833	175,336
Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	6,319,893	3,604,950
Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,520,542	982,421
Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,561,800	2,113,285
Noncommercial | 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	120,097	122,792
Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,117,454	386,452
Non-PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	57,321	44,167
60-89 Days Past Due	19,548	14,236
90 Days or Greater	24,598	30,828
Total	101,467	89,231
Current	17,481,500	12,015,067
Loans and leases, not acquired in a transfer accounted for as debt securities	17,582,967	12,104,298
Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,796	1,603
60-89 Days Past Due	621	9
90 Days or Greater	385	457
Total	2,802	2,069
Current	547,766	317,778
Loans and leases, not acquired in a transfer accounted for as debt securities	550,568	319,847
Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	11,367	11,131
60-89 Days Past Due	4,782	3,601
90 Days or Greater	8,061	14,407
Total	24,210	29,139
Current	7,528,738	6,333,351
Loans and leases, not acquired in a transfer accounted for as debt securities	7,552,948	6,362,490
Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	206	139
60-89 Days Past Due	70	210
90 Days or Greater	102	470
Total	378	819
Current	244,497	177,935
Loans and leases, not acquired in a transfer accounted for as debt securities	244,875	178,754
Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	2,843	3,336
60-89 Days Past Due	1,545	682
90 Days or Greater	378	436
Total	4,766	4,454
Current	1,984,168	1,076,704
Loans and leases, not acquired in a transfer accounted for as debt securities	1,988,934	1,081,158
Non-PCI Loans | Commercial | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,631	789
60-89 Days Past Due	8	1,341
90 Days or Greater	2	101
Total	1,641	2,231
Current	570,275	379,532
Loans and leases, not acquired in a transfer accounted for as debt securities	571,916	381,763
Non-PCI Loans | Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	146	0
60-89 Days Past Due	1,966	85
90 Days or Greater	0	0
Total	2,112	85
Current	351,721	175,251
Loans and leases, not acquired in a transfer accounted for as debt securities	353,833	175,336
Non-PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	39,332	27,169
60-89 Days Past Due	10,556	8,308
90 Days or Greater	15,670	14,957
Current	6,254,335	3,554,516
Loans and leases, not acquired in a transfer accounted for as debt securities	6,319,893	3,604,950
Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	23,288	12,885
60-89 Days Past Due	6,018	4,658
90 Days or Greater	8,955	9,578
Total	38,261	27,121
Current	2,482,281	955,300
Loans and leases, not acquired in a transfer accounted for as debt securities	2,520,542	982,421
Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	11,097	10,977
60-89 Days Past Due	2,433	2,378
90 Days or Greater	5,463	4,450
Total	18,993	17,805
Current	2,542,807	2,095,480
Loans and leases, not acquired in a transfer accounted for as debt securities	2,561,800	2,113,285
Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	370	1,193
60-89 Days Past Due	486	317
90 Days or Greater	147	256
Total	1,003	1,766
Current	119,094	121,026
Loans and leases, not acquired in a transfer accounted for as debt securities	120,097	122,792
Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	4,577	2,114
60-89 Days Past Due	1,619	955
90 Days or Greater	1,105	673
Total	7,301	3,742
Current	1,110,153	382,710
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 1,117,454	$ 386,452