Loans and Leases (Loans and Leases Outstanding) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Covered loans	$ 1,897,097	[1]	$ 2,362,152	[2]	$ 2,557,450	[1]
Noncovered loans and leases	11,455,233	[1]	11,581,637	[2]	11,603,526	[1]
Total loans and leases	13,352,330		13,943,789		14,160,976
Commercial Mortgage
Covered loans	1,542,482		1,872,685		2,013,636
Noncovered loans and leases	7,844,572		7,866,572		7,817,695
Non-Commercial Loans
Covered loans	354,615		489,467		543,814
Noncovered loans and leases	3,610,661		3,715,065		3,785,831
Construction and Land Development | Commercial Mortgage
Covered loans	258,388		338,873		405,658
Noncovered loans and leases	319,743		381,163		416,719
Construction and Land Development | Non-Commercial Loans
Covered loans	26,408		105,536		115,126
Noncovered loans and leases	132,352		137,271		139,185
Commercial Mortgage | Commercial Mortgage
Covered loans	1,109,048		1,260,589		1,310,083
Noncovered loans and leases	5,171,964		5,104,993		4,996,036
Other Commercial Real Estate | Commercial Mortgage
Covered loans	113,954		158,394		159,007
Noncovered loans and leases	158,767		144,771		144,538
Commercial and Industry | Commercial Mortgage
Noncovered loans and leases	1,740,435		1,764,407		1,797,581
Lease Financing | Commercial Mortgage
Covered loans	0		57		162
Noncovered loans and leases	321,908		312,869		304,039
Other | Commercial Mortgage
Covered loans	1,305		1,330		1,473
Noncovered loans and leases	131,755		158,369		158,782
Residential Mortgage | Non-Commercial Loans
Covered loans	289,160		327,568		380,405
Noncovered loans and leases	814,877		784,118		816,738
Revolving Mortgage | Non-Commercial Loans
Covered loans	37,280		51,552		39,709
Noncovered loans and leases	2,244,459		2,296,306		2,302,482
Consumer | Non-Commercial Loans
Covered loans	1,767		4,811		8,574
Noncovered loans and leases	$ 418,973		$ 497,370		$ 527,426

[1] Unaudited

[2] Derived from 2011 Annual Report on Form 10-K.