Loans and Leases (Composition of the Loans and Leases Outstanding By Credit Quality Indicator) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 17,582,967	$ 12,104,298
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	1,186,498	1,029,426	1,809,235
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	11,263,074	8,499,348
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	726,123	781,307
Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	550,568	319,847
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	78,079	78,915
Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	7,552,948	6,362,490
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	577,518	642,891
Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	244,875	178,754
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	40,193	41,381
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,988,934	1,081,158
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	27,254	17,254
Commercial | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	571,916	381,763
Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	353,833	175,336
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	3,079	866
Commercial | Consumer and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	3,079	866
Commercial | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	10,825,323	8,092,174
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	342,172	330,555
Commercial | Pass | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	525,711	308,231
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	13,514	2,619
Commercial | Pass | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	7,284,714	6,094,505
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	300,187	296,824
Commercial | Pass | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	242,053	174,913
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	11,033	22,225
Commercial | Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,859,415	964,840
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	16,637	8,021
Commercial | Pass | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	564,319	375,371
Commercial | Pass | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	349,111	174,314
Commercial | Pass | Consumer and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	801	866
Commercial | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	182,453	147,325
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	125,195	146,841
Commercial | Special Mention | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	20,025	8,620
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	6,063	15,530
Commercial | Special Mention | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	129,247	119,515
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	98,724	125,295
Commercial | Special Mention | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	909	1,362
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	16,271	3,431
Commercial | Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	27,683	14,686
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	4,137	2,585
Commercial | Special Mention | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	3,205	2,160
Commercial | Special Mention | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,384	982
Commercial | Special Mention | Consumer and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	0	0
Commercial | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	157,333	156,956
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	247,138	244,122
Commercial | Substandard | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	4,720	2,944
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	53,739	52,228
Commercial | Substandard | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	134,677	141,913
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	171,920	179,657
Commercial | Substandard | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,765	2,216
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	12,889	7,012
Commercial | Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	8,878	6,352
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	6,312	5,225
Commercial | Substandard | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	3,955	3,491
Commercial | Substandard | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	3,338	40
Commercial | Substandard | Consumer and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	2,278	0
Commercial | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,895	6,022
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	9,241	57,877
Commercial | Doubtful | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	0	52
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	2,809	7,436
Commercial | Doubtful | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,366	5,159
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	6,302	40,471
Commercial | Doubtful | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	0	75
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	0	8,713
Commercial | Doubtful | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	164	144
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	130	1,257
Commercial | Doubtful | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	365	592
Commercial | Doubtful | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	0	0
Commercial | Doubtful | Consumer and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	0	0
Commercial | Ungraded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	95,070	96,871
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	2,377	1,912
Commercial | Ungraded | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	112	0
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	1,954	1,102
Commercial | Ungraded | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,944	1,398
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	385	644
Commercial | Ungraded | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	148	188
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	0	0
Commercial | Ungraded | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	92,794	95,136
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	38	166
Commercial | Ungraded | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	72	149
Commercial | Ungraded | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	0	0
Commercial | Ungraded | Consumer and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	0	0
Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	6,319,893	3,604,950
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	460,375	248,119
Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,520,542	982,421
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	382,340	213,851
Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	2,561,800	2,113,285
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	74,109	30,834
Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	120,097	122,792
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	912	2,583
Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, not acquired in a transfer accounted for as debt securities	1,117,454	386,452
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	3,014	851
Non-PCI Loans [Member] | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	398,225	192,179
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	460,375	248,119
30-59 Days Past Due	12,984	17,402
60-89 Days Past Due	10,443	6,544
90 Days or Greater	38,723	31,994
Non-PCI Loans [Member] | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	326,589	162,771
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	382,340	213,851
30-59 Days Past Due	11,432	15,261
60-89 Days Past Due	10,073	6,544
90 Days or Greater	34,246	29,275
Non-PCI Loans [Member] | Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	68,548	26,642
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	74,109	30,834
30-59 Days Past Due	1,405	2,138
60-89 Days Past Due	345	0
90 Days or Greater	3,811	2,054
Non-PCI Loans [Member] | Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	506	1,925
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	912	2,583
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
90 Days or Greater	406	658
Non-PCI Loans [Member] | Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,582	841
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	3,014	851
30-59 Days Past Due	147	3
60-89 Days Past Due	25	0
90 Days or Greater	$ 260	$ 7