Allowance for Loan and Lease Losses (Troubled Debt Restructuring) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Financing Receivable, Modifications [Line Items]
Accruing	$ 173,888		$ 253,388
Nonaccruing	35,857		79,782
Financing Receivable, Modifications, Recorded Investment	209,745	333,170	333,170
Minimum amount of nonaccrual status for loans to qualify to be individually evaluated for impairment	500,000
Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	66,840	89,845
Financing Receivable, Modifications, Recorded Investment	95,514	139,963
Acquired Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	114,231	193,207
Commercial
Financing Receivable, Modifications [Line Items]
Accruing	144,229		220,397
Nonaccruing	31,398		73,954
Financing Receivable, Modifications, Recorded Investment	175,627		294,351
Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Accruing	24,394		47,368
Nonaccruing	2,505		26,920
Financing Receivable, Modifications, Recorded Investment	26,899		74,288
Commercial | Construction and land development | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	493	14,930
Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Accruing	105,775		151,728
Nonaccruing	26,669		37,603
Financing Receivable, Modifications, Recorded Investment	132,444		189,331
Commercial | Mortgage | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	44,818	50,532
Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Accruing	3,548		10,137
Nonaccruing	1,330		2,194
Financing Receivable, Modifications, Recorded Investment	4,878		12,331
Commercial | Other commercial real estate | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	1,937	2,319
Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Accruing	10,364		10,940
Nonaccruing	894		7,237
Financing Receivable, Modifications, Recorded Investment	11,258		18,177
Commercial | Commercial and industrial | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	2,978	6,972
Commercial | Lease financing
Financing Receivable, Modifications [Line Items]
Accruing	148		224
Nonaccruing	0		0
Financing Receivable, Modifications, Recorded Investment	148		224
Commercial | Lease financing | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	1,000	1,075
Noncommerical
Financing Receivable, Modifications [Line Items]
Accruing	29,659		32,991
Nonaccruing	4,459		5,828
Financing Receivable, Modifications, Recorded Investment	34,118		38,819
Noncommerical | Mortgage
Financing Receivable, Modifications [Line Items]
Accruing	24,913		28,777
Nonaccruing	3,996		5,828
Financing Receivable, Modifications, Recorded Investment	28,909		34,605
Noncommerical | Mortgage | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	15,119	12,603
Noncommerical | Construction and land development
Financing Receivable, Modifications [Line Items]
Accruing	476		1,657
Nonaccruing	463		0
Financing Receivable, Modifications, Recorded Investment	939		1,657
Noncommerical | Construction and land development | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	463	668
Noncommerical | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Accruing	3,058		48
Nonaccruing	0		0
Financing Receivable, Modifications, Recorded Investment	3,058		48
Noncommerical | Revolving mortgage | Originated Loans
Financing Receivable, Modifications [Line Items]
Nonaccruing	0	0
Noncommerical | Consumer and Other
Financing Receivable, Modifications [Line Items]
Accruing	1,212		2,509
Nonaccruing	0		0
Financing Receivable, Modifications, Recorded Investment	$ 1,212		$ 2,509