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	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011
Total Loans and Leases	$ 11,489,529	[1]	$ 11,581,637	[2]	$ 11,392,351	[1]
Commercial Mortgage [Member]
Total Loans and Leases	7,830,041		7,866,572		7,546,718
Commercial Mortgage [Member] | Construction and Land Development [Member]
Total Loans and Leases	346,557		381,163		373,769
Commercial Mortgage [Member] | Commercial Mortgage [Member]
Total Loans and Leases	1,739,724		1,764,407		1,792,042
Commercial Mortgage [Member] | Other Commercial Real Estate [Member]
Total Loans and Leases	150,316		144,771		147,150
Commercial Mortgage [Member] | Commercial And Industrial [Member]
Total Loans and Leases	1,739,724		1,764,407		1,792,042
Commercial Mortgage [Member] | Lease Financing [Member]
Total Loans and Leases	315,704		312,869		295,994
Commercial Mortgage [Member] | Other Loans [Member]
Total Loans and Leases	149,792		158,369		174,370
Non-Commercial Loans [Member]
Total Loans and Leases	3,659,488		3,715,065		3,845,633
Non-Commercial Loans [Member] | Construction and Land Development [Member]
Total Loans and Leases	132,677		137,271		145,864
Non-Commercial Loans [Member] | Residential Mortgage [Member]
Total Loans and Leases	793,612		784,118		808,650
Non-Commercial Loans [Member] | Revolving Mortgage [Member]
Total Loans and Leases	2,282,138		2,296,306		2,299,668
Non-Commercial Loans [Member] | Consumer [Member]
Total Loans and Leases	451,061		497,370		591,451
Noncovered Loans [Member]
31-60 days past due	56,153		46,999		59,957
61-90 days past due	14,560		13,647		14,290
Greater Than 90 Days	40,906		39,282		47,770
Total Past Due	111,619		99,928		122,017
Current	11,377,910		11,481,709		11,270,334
Total Loans and Leases	11,489,529		11,581,637		11,392,351
Noncovered Loans [Member] | Commercial Mortgage [Member]
31-60 days past due	27,947		18,308		21,304
61-90 days past due	6,548		4,438		4,576
Greater Than 90 Days	13,939		15,626		19,091
Total Past Due	48,434		38,372		44,971
Current	5,079,514		5,066,621		4,718,422
Total Loans and Leases	5,127,948		5,104,993		4,763,393
Noncovered Loans [Member] | Other Commercial Real Estate [Member]
31-60 days past due	787		657		860
61-90 days past due	43		147		147
Greater Than 90 Days	193		561		585
Total Past Due	1,023		1,365		1,592
Current	149,293		143,406		145,558
Total Loans and Leases	150,316		144,771		147,150
Noncovered Loans [Member] | Commercial And Industrial [Member]
31-60 days past due	5,522		5,235		5,016
61-90 days past due	1,006		1,230		1,110
Greater Than 90 Days	1,754		1,438		4,700
Total Past Due	8,282		7,903		10,826
Current	1,731,442		1,756,504		1,781,216
Total Loans and Leases	1,739,724		1,764,407		1,792,042
Noncovered Loans [Member] | Lease Financing [Member]
31-60 days past due	824		637		841
61-90 days past due	99		212		269
Greater Than 90 Days	1,269		620		864
Total Past Due	2,192		1,469		1,974
Current	313,512		311,400		294,020
Total Loans and Leases	315,704		312,869		295,994
Noncovered Loans [Member] | Other Loans [Member]
31-60 days past due	0		0		2
61-90 days past due	0		0		0
Greater Than 90 Days	0		0		0
Total Past Due	0		0		2
Current	149,792		158,369		174,368
Total Loans and Leases	149,792		158,369		174,370
Noncovered Loans [Member] | Residential Mortgage [Member]
31-60 days past due	14,001		11,790		16,439
61-90 days past due	2,812		2,686		2,207
Greater Than 90 Days	13,388		12,529		12,022
Total Past Due	30,201		27,005		30,668
Current	763,411		757,113		777,982
Total Loans and Leases	793,612		784,118		808,650
Noncovered Loans [Member] | Revolving Mortgage [Member]
31-60 days past due	2,349		3,437		5,462
61-90 days past due	1,212		2,042		3,285
Greater Than 90 Days	4,486		4,316		3,195
Total Past Due	8,047		9,795		11,942
Current	2,274,091		2,286,511		2,287,726
Total Loans and Leases	2,282,138		2,296,306		2,299,668
Noncovered Loans [Member] | Consumer [Member]
31-60 days past due	1,885		3,514		6,911
61-90 days past due	1,028		1,271		2,216
Greater Than 90 Days	1,727		1,443		1,780
Total Past Due	4,640		6,228		10,907
Current	446,421		491,142		580,544
Total Loans and Leases	451,061		497,370		591,451
Noncovered Loans [Member] | Commercial Mortgage [Member] | Construction and Land Development [Member]
31-60 days past due	2,030		2,623		2,006
61-90 days past due	1,366		1,494		116
Greater Than 90 Days	3,288		2,177		3,572
Total Past Due	6,684		6,294		5,694
Current	339,873		374,869		368,075
Total Loans and Leases	346,557		381,163		373,769
Noncovered Loans [Member] | Non-Commercial Loans [Member]
Total Loans and Leases	3,659,488		3,715,065		3,845,633
Noncovered Loans [Member] | Non-Commercial Loans [Member] | Construction and Land Development [Member]
31-60 days past due	808		798		1,116
61-90 days past due	446		127		364
Greater Than 90 Days	862		572		1,961
Total Past Due	2,116		1,497		3,441
Current	130,561		135,774		142,423
Total Loans and Leases	132,677		137,271		145,864
Noncovered Loans [Member] | Non-Commercial Loans [Member] | Residential Mortgage [Member]
Total Loans and Leases	793,612		784,118		808,650
Noncovered Loans [Member] | Non-Commercial Loans [Member] | Revolving Mortgage [Member]
Total Loans and Leases	2,282,138		2,296,306		2,299,668
Noncovered Loans [Member] | Non-Commercial Loans [Member] | Consumer [Member]
Total Loans and Leases	$ 451,061		$ 497,370		$ 591,451

[1] Unaudited

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