Allowance for Loan and Lease Losses (Summary of Activity In Allowance for Loan and Lease Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance	$ 272,500	[1]	$ 232,597	[1]	$ 272,500	[1]	$ 270,144	[2]	$ 232,597	[1]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	272,500	[1]	232,597	[1]	272,500	[1]	270,144	[2]	232,597	[1]
Loans and Leases Evaluated for Impairment [Abstract]
Net loans and leases	13,400,898	[1]	13,817,888	[1]	13,400,898	[1]	13,673,645	[2]	13,817,888	[1]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
Allowance relating to pooled loans	272,500	[1]	232,597	[1]	272,500	[1]	270,144	[2]	232,597	[1]
Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	89,261	[3]	51,248	[3]	86,117	[3]			54,629	[3]
Charge-offs	(12,747)	[3]	(31,254)	[3]
Recoveries	0	[3]	2,078	[3]
Provisions	9,603	[3]	32,557	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	86,117	[3]	54,629	[3]			89,261	[3]
Loans and leases acquired with deteriorated credit quality	2,183,869		2,658,134				2,362,152
Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	180,883		176,517		186,383				177,968
Charge-offs	(17,632)		(12,422)
Recoveries	2,020		2,011
Provisions	21,112		11,862
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	11,349		12,115				7,962
ALLL for loans and leases collectively evaluated for impairment	160,212		151,758				158,799
Non-specific ALLL	14,822		14,095				14,122
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	154,275		123,728				156,301
Loans and leases collectively evaluated for impairment	11,335,254		11,268,623				11,425,336
Net loans and leases	11,489,529		11,392,351				11,581,637
Construction and Land Development - Commercial [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	16,693	[3]	20,654	[3]	12,736	[3]			20,419	[3]
Charge-offs	(1,387)	[3]	(4,318)	[3]
Recoveries	0	[3]	1,188	[3]
Provisions	(2,570)	[3]	2,895	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	12,736	[3]	20,419	[3]			16,693	[3]
Loans and leases acquired with deteriorated credit quality	310,601		402,316				338,873
Construction and Land Development - Commercial [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,467		10,512		6,608				10,728
Charge-offs	(5,729)		(711)
Recoveries	42		92
Provisions	6,828		835
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	2,605		6,170				1,139
ALLL for loans and leases collectively evaluated for impairment	4,003		4,558				4,328
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	21,621		30,369				26,782
Loans and leases collectively evaluated for impairment	324,936		343,400				354,381
Net loans and leases	346,557		373,769				381,163
Commercial Mortgage [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	39,557	[3]	13,199	[3]	39,744	[3]			14,649	[3]
Charge-offs	(6,211)	[3]	(6,775)	[3]
Recoveries	0	[3]	426	[3]
Provisions	6,398	[3]	7,799	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	39,744	[3]	14,649	[3]			39,557	[3]
Loans and leases acquired with deteriorated credit quality	1,195,541		1,432,632				1,260,589
Commercial Mortgage [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	67,486		64,772		72,155				66,190
Charge-offs	(2,464)		(1,801)
Recoveries	996		157
Provisions	6,137		3,062
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	6,662		4,716				5,266
ALLL for loans and leases collectively evaluated for impairment	65,493		61,474				62,220
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	95,265		69,017				92,872
Loans and leases collectively evaluated for impairment	5,032,683		4,694,376				5,012,121
Net loans and leases	5,127,948		4,763,393				5,104,993
Other Commercial Real Estate [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	16,862	[3]	4,148	[3]	11,150	[3]			4,905	[3]
Charge-offs	0	[3]	(4,117)	[3]
Recoveries	0	[3]	4	[3]
Provisions	(5,712)	[3]	4,870	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	11,150	[3]	4,905	[3]			16,862	[3]
Loans and leases acquired with deteriorated credit quality	144,978		163,305				158,394
Other Commercial Real Estate [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,169		2,200		2,248				2,204
Charge-offs	(142)		0
Recoveries	0		6
Provisions	221		(2)
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	256		62				283
ALLL for loans and leases collectively evaluated for impairment	1,992		2,142				1,886
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	2,721		946				5,686
Loans and leases collectively evaluated for impairment	147,595		146,204				139,085
Net loans and leases	150,316		147,150				144,771
Commercial And Industrial [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,500	[3]	6,828	[3]	13,728	[3]			6,712	[3]
Charge-offs	(3,189)	[3]	(13,141)	[3]
Recoveries	0	[3]	252	[3]
Provisions	11,417	[3]	12,773	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	13,728	[3]	6,712	[3]			5,500	[3]
Loans and leases acquired with deteriorated credit quality	93,261		171,041				113,442
Commercial And Industrial [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	23,723		24,089		24,246				24,365
Charge-offs	(1,447)		(2,057)
Recoveries	250		313
Provisions	1,720		2,020
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	838		727				640
ALLL for loans and leases collectively evaluated for impairment	23,408		23,638				23,083
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	17,261		14,631				15,996
Loans and leases collectively evaluated for impairment	1,722,463		1,777,411				1,748,411
Net loans and leases	1,739,724		1,792,042				1,764,407
Lease Financing [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13	[3]	0	[3]	3	[3]			0	[3]
Charge-offs	0	[3]	0	[3]
Recoveries	0	[3]	0	[3]
Provisions	(10)	[3]	0	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	3	[3]	0	[3]			13	[3]
Loans and leases acquired with deteriorated credit quality	45		271				57
Lease Financing [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,288		3,384		3,320				3,369
Charge-offs	(191)		(12)
Recoveries	31		11
Provisions	192		(14)
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	19		73				17
ALLL for loans and leases collectively evaluated for impairment	3,301		3,296				3,271
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	375		963				328
Loans and leases collectively evaluated for impairment	315,329		295,031				312,541
Net loans and leases	315,704		295,994				312,869
Other Loans [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,315		1,473		1,281				1,419
Charge-offs	0		(38)
Recoveries	4		1
Provisions	(38)		(17)
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0		0				14
ALLL for loans and leases collectively evaluated for impairment	1,281		1,419				1,301
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	0		0				193
Loans and leases collectively evaluated for impairment	149,792		174,370				158,176
Net loans and leases	149,792		174,370				158,369
Residential Mortgage [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,433	[3]	113	[3]	4,732	[3]			1,012	[3]
Charge-offs	(1,955)	[3]	(323)	[3]
Recoveries	0	[3]	60	[3]
Provisions	1,254	[3]	1,162	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	4,732	[3]	1,012	[3]			5,433	[3]
Loans and leases acquired with deteriorated credit quality	298,538		347,393				327,568
Residential Mortgage [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,879		7,009		9,107				7,129
Charge-offs	(1,035)		(1,688)
Recoveries	42		787
Provisions	1,221		1,021
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	782		354				411
ALLL for loans and leases collectively evaluated for impairment	8,325		6,775				8,468
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	12,772		7,186				9,776
Loans and leases collectively evaluated for impairment	780,840		801,464				774,342
Net loans and leases	793,612		808,650				784,118
Revolving Mortgage [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	77	[3]	676	[3]	1,027	[3]			1,451	[3]
Charge-offs	0	[3]	(2,072)	[3]
Recoveries	0	[3]	0	[3]
Provisions	950	[3]	2,847	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	1,027	[3]	1,451	[3]			77	[3]
Loans and leases acquired with deteriorated credit quality	50,016		23,409				51,552
Revolving Mortgage [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	27,045		18,016		26,911				19,363
Charge-offs	(2,940)		(2,363)
Recoveries	216		186
Provisions	2,590		3,524
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0		0				0
ALLL for loans and leases collectively evaluated for impairment	26,911		19,363				27,045
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	0		0				0
Loans and leases collectively evaluated for impairment	2,282,138		2,299,668				2,296,306
Net loans and leases	2,282,138		2,299,668				2,296,306
Construction And Land Development - Non - Commercial [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,652	[3]	5,607	[3]	2,720	[3]			5,468	[3]
Charge-offs	0	[3]	(496)	[3]
Recoveries	0	[3]	148	[3]
Provisions	(1,932)	[3]	209	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	2,720	[3]	5,468	[3]			4,652	[3]
Loans and leases acquired with deteriorated credit quality	85,555		111,425				105,536
Construction And Land Development - Non - Commercial [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,427		1,751		1,397				1,328
Charge-offs	(676)		(456)
Recoveries	7		65
Provisions	639		(32)
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	145		5				145
ALLL for loans and leases collectively evaluated for impairment	1,252		1,323				1,282
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	3,345		514				3,676
Loans and leases collectively evaluated for impairment	129,332		145,350				133,595
Net loans and leases	132,677		145,864				137,271
Consumer [Member] | Covered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	474	[3]	23	[3]	277	[3]			13	[3]
Charge-offs	(5)	[3]	(12)	[3]
Recoveries	0	[3]	0	[3]
Provisions	(192)	[3]	2	[3]
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	277	[3]	13	[3]			474	[3]
Loans and leases acquired with deteriorated credit quality	5,334		6,342				6,141
Consumer [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	25,962		29,448		24,288				27,778
Charge-offs	(3,008)		(3,296)
Recoveries	432		393
Provisions	902		1,233
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	42		8				47
ALLL for loans and leases collectively evaluated for impairment	24,246		27,770				25,915
Non-specific ALLL	0		0				0
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	915		102				992
Loans and leases collectively evaluated for impairment	450,146		591,349				496,378
Net loans and leases	451,061		591,451				497,370
Non-Specific [Member] | Noncovered Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	14,122		13,863		14,822				14,095
Charge-offs	0		0
Recoveries	0		0
Provisions	700		232
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0		0				0
ALLL for loans and leases collectively evaluated for impairment	0		0				0
Non-specific ALLL	14,822		14,095				14,122
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	0		0				0
Loans and leases collectively evaluated for impairment	0		0				0
Net loans and leases	0		0				0
Pooled Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance	2,936				2,936		1,099
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	2,936				2,936		1,099
Loan and Lease Acquired with Deteriorated Credit uality [Abstract]
Allowance relating to pooled loans	$ 2,936				$ 2,936		$ 1,099

[1] Unaudited

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

[3] The allowance of $2,936 at March 31, 2012 and $1,099 at December 31, 2011 relating to pooled loans is included in the loan classes above based on the primary loan class within each pool.