Loans and Leases (Loans and Leases Outstanding) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011
Covered loans	$ 1,999,351	[1]	$ 2,362,152	[2]	$ 2,399,738	[1]
Noncovered loans and leases	11,462,458	[1]	11,581,637	[2]	11,528,854	[1]
Total loans and leases	13,461,809		13,943,789		13,928,592
Commercial Mortgage
Covered loans	1,598,579		1,872,685		1,947,422
Noncovered loans and leases	7,825,628		7,866,572		7,697,242
Non-Commercial Loans
Covered loans	400,772		489,467		452,316
Noncovered loans and leases	3,636,830		3,715,065		3,831,612
Construction and Land Development | Commercial Mortgage
Covered loans	272,445		338,873		338,650
Noncovered loans and leases	329,151		381,163		407,134
Construction and Land Development | Non-Commercial Loans
Covered loans	39,294		105,536		82,177
Noncovered loans and leases	127,726		137,271		145,445
Commercial Mortgage | Commercial Mortgage
Covered loans	1,142,677		1,260,589		1,307,775
Noncovered loans and leases	5,149,696		5,104,993		4,861,457
Other Commercial Real Estate | Commercial Mortgage
Covered loans	115,787		158,394		173,606
Noncovered loans and leases	162,579		144,771		148,977
Lease Financing | Commercial Mortgage
Covered loans	0		57		224
Noncovered loans and leases	320,703		312,869		303,104
Other | Commercial Mortgage
Covered loans	1,228		1,330		1,675
Noncovered loans and leases	140,738		158,369		170,758
Residential Mortgage | Non-Commercial Loans
Covered loans	322,053		327,568		354,033
Noncovered loans and leases	809,230		784,118		825,610
Revolving Mortgage | Non-Commercial Loans
Covered loans	37,110		51,552		11,933
Noncovered loans and leases	2,268,210		2,296,306		2,303,687
Consumer | Non-Commercial Loans
Covered loans	2,315		4,811		4,173
Noncovered loans and leases	$ 431,664		$ 497,370		$ 556,870

[1] Unaudited

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