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	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	$ 11,455,233	[1]	$ 11,581,637	[2]	$ 11,603,526	[1]
Commercial Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	7,844,572		7,866,572		7,817,695
Commercial Mortgage | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	319,743		381,163		416,719
Commercial Mortgage | Other Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	158,767		144,771		144,538
Commercial Mortgage | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	1,740,435		1,764,407		1,797,581
Commercial Mortgage | Lease Financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	321,908		312,869		304,039
Commercial Mortgage | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	131,755		158,369		158,782
Non-Commercial Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	3,610,661		3,715,065		3,785,831
Non-Commercial Loans | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	132,352		137,271		139,185
Non-Commercial Loans | Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	814,877		784,118		816,738
Non-Commercial Loans | Revolving Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	2,244,459		2,296,306		2,302,482
Non-Commercial Loans | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	418,973		497,370		527,426
Noncovered Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	62,404		46,999		30,157
60-89 Days Past Due	23,330		13,647		10,475
90 Days or Greater	43,577		39,282		45,507
Total Past Due	129,311		99,928		86,139
Current	11,325,922		11,481,709		11,517,387
Total Loans and Leases	11,455,233		11,581,637		11,603,526
Noncovered Loans | Commercial Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	19,329		18,308		13,381
60-89 Days Past Due	10,223		4,438		3,765
90 Days or Greater	15,021		15,626		16,838
Total Past Due	44,573		38,372		33,984
Current	5,127,391		5,066,621		4,962,052
Total Loans and Leases	5,171,964		5,104,993		4,996,036
Noncovered Loans | Other Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	783		657		93
60-89 Days Past Due	0		147		0
90 Days or Greater	1,049		561		965
Total Past Due	1,832		1,365		1,058
Current	156,935		143,406		143,480
Total Loans and Leases	158,767		144,771		144,538
Noncovered Loans | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	6,734		5,235		1,417
60-89 Days Past Due	965		1,230		1,092
90 Days or Greater	1,826		1,438		1,548
Total Past Due	9,525		7,903		4,057
Current	1,730,910		1,756,504		1,793,524
Total Loans and Leases	1,740,435		1,764,407		1,797,581
Noncovered Loans | Lease Financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	947		637		879
60-89 Days Past Due	153		212		180
90 Days or Greater	514		620		96
Total Past Due	1,614		1,469		1,155
Current	320,294		311,400		302,884
Total Loans and Leases	321,908		312,869		304,039
Noncovered Loans | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0		0		18
60-89 Days Past Due	0		0		0
90 Days or Greater	0		0		0
Total Past Due	0		0		18
Current	131,755		158,369		158,764
Total Loans and Leases	131,755		158,369		158,782
Noncovered Loans | Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	16,281		11,790		2,303
60-89 Days Past Due	6,635		2,686		3,022
90 Days or Greater	11,521		12,529		15,835
Total Past Due	34,437		27,005		21,160
Current	780,440		757,113		795,578
Total Loans and Leases	814,877		784,118		816,738
Noncovered Loans | Revolving Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	12,894		3,437		3,987
60-89 Days Past Due	4,033		2,042		924
90 Days or Greater	3,767		4,316		6,081
Total Past Due	20,694		9,795		10,992
Current	2,223,765		2,286,511		2,291,490
Total Loans and Leases	2,244,459		2,296,306		2,302,482
Noncovered Loans | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	2,508		3,514		2,369
60-89 Days Past Due	959		1,271		1,361
90 Days or Greater	1,114		1,443		1,541
Total Past Due	4,581		6,228		5,271
Current	414,392		491,142		522,155
Total Loans and Leases	418,973		497,370		527,426
Noncovered Loans | Commercial Mortgage | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	340		2,623		1,506
60-89 Days Past Due	235		1,494		131
90 Days or Greater	7,685		2,177		2,089
Total Past Due	8,260		6,294		3,726
Current	311,483		374,869		412,993
Total Loans and Leases	319,743		381,163		416,719
Noncovered Loans | Non-Commercial Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	3,610,661		3,715,065		3,785,831
Noncovered Loans | Non-Commercial Loans | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	2,588		798		4,204
60-89 Days Past Due	127		127		0
90 Days or Greater	1,080		572		514
Total Past Due	3,795		1,497		4,718
Current	128,557		135,774		134,467
Total Loans and Leases	132,352		137,271		139,185
Noncovered Loans | Non-Commercial Loans | Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	814,877		784,118		816,738
Noncovered Loans | Non-Commercial Loans | Revolving Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	2,244,459		2,296,306		2,302,482
Noncovered Loans | Non-Commercial Loans | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	$ 418,973		$ 497,370		$ 527,426

[1] Unaudited

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