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				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Loans and Leases Evaluated for Impairment [Abstract]
Net loans and leases	$ 13,188,880	[1]	$ 13,678,542	[1]	$ 13,188,880	[1]	$ 13,678,542	[1]	$ 13,673,645	[2]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
Allowance for loan and lease losses	272,929	[1]	250,050	[1]	272,929	[1]	250,050	[1]	270,144	[2]
Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	86,117	[3]	54,629	[3]	89,261	[3]	51,248	[3]
Charge-offs	(17,140)	[3]	(26,544)	[3]	(29,887)	[3]	(55,728)	[3]
Recoveries	142	[3]	154	[3]	142	[3]	162	[3]
Provisions	18,678	[3]	41,196	[3]	28,281	[3]	73,753	[3]
Ending balance	87,797	[3]	69,435	[3]	87,797	[3]	69,435	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	87,797	[3]	69,435	[3]	87,797	[3]	69,435	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	87,797	[3]	69,435	[3]	87,797	[3]	69,435	[3]	89,261	[3]
Loans and leases acquired with deteriorated credit quality	1,999,351		2,399,738		1,999,351		2,399,738		2,362,152
Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	186,383		177,968		180,883		176,517
Charge-offs	(13,794)		(11,678)		(31,425)		(22,131)
Recoveries	(1,554)		(1,544)		(3,573)		(1,586)
Provisions	10,989		12,781		32,101		24,643
Ending balance	185,132		180,615		185,132		180,615
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	16,212		11,925		16,212		11,925		7,962
ALLL for loans and leases collectively evaluated for impairment	152,978		154,612		152,978		154,612		158,799
Non-specific ALLL	15,942		14,078		15,942		14,078		14,122
Total allowance for loan and lease losses	185,132		180,615		185,132		180,615
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	221,699		129,188		221,699		129,188		156,301
Loans and leases collectively evaluated for impairment	11,240,759		11,399,666		11,240,759		11,399,666		11,425,336
Net loans and leases	11,462,458		11,528,854		11,462,458		11,528,854		11,581,637
Construction and Land Development - Commercial | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	12,736	[3]	20,419	[3]	16,693	[3]	20,654	[3]
Charge-offs	(3,639)	[3]	(5,156)	[3]	(5,026)	[3]	(9,952)	[3]
Recoveries	0	[3]	0	[3]	0	[3]	0	[3]
Provisions	6,886	[3]	8,971	[3]	4,316	[3]	13,532	[3]
Ending balance	15,983	[3]	24,234	[3]	15,983	[3]	24,234	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	15,983	[3]	24,234	[3]	15,983	[3]	24,234	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	15,983	[3]	24,234	[3]	15,983	[3]	24,234	[3]	16,693	[3]
Loans and leases acquired with deteriorated credit quality	272,445		338,650		272,445		338,650		338,873
Construction and Land Development - Commercial | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	6,608		10,728		5,467		10,512
Charge-offs	(3,492)		(308)		(9,221)		(395)
Recoveries	(228)		(13)		(269)		(37)
Provisions	1,712		(741)		8,541		(462)
Ending balance	5,056		9,692		5,056		9,692
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	1,621		5,526		1,621		5,526		1,139
ALLL for loans and leases collectively evaluated for impairment	3,435		4,166		3,435		4,166		4,328
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	5,056		9,692		5,056		9,692
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	28,230		28,274		28,230		28,274		26,782
Loans and leases collectively evaluated for impairment	300,921		378,860		300,921		378,860		354,381
Net loans and leases	329,151		407,134		329,151		407,134		381,163
Commercial Mortgage | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	39,744	[3]	14,649	[3]	39,557	[3]	13,199	[3]
Charge-offs	(9,182)	[3]	(11,409)	[3]	(15,393)	[3]	(24,007)	[3]
Recoveries	0	[3]	7	[3]	0	[3]	15	[3]
Provisions	5,429	[3]	18,846	[3]	11,827	[3]	32,886	[3]
Ending balance	35,991	[3]	22,093	[3]	35,991	[3]	22,093	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	35,991	[3]	22,093	[3]	35,991	[3]	22,093	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	35,991	[3]	22,093	[3]	35,991	[3]	22,093	[3]	39,557	[3]
Loans and leases acquired with deteriorated credit quality	1,142,677		1,307,775		1,142,677		1,307,775		1,260,589
Commercial Mortgage | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	72,155		66,190		67,486		64,772
Charge-offs	(1,556)		(825)		(4,020)		(3,961)
Recoveries	(12)		(546)		(1,008)		(555)
Provisions	355		1,212		6,492		5,757
Ending balance	70,966		67,123		70,966		67,123
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	9,745		5,272		9,745		5,272		5,266
ALLL for loans and leases collectively evaluated for impairment	61,221		61,851		61,221		61,851		62,220
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	70,966		67,123		70,966		67,123
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	139,235		69,806		139,235		69,806		92,872
Loans and leases collectively evaluated for impairment	5,010,461		4,791,651		5,010,461		4,791,651		5,012,121
Net loans and leases	5,149,696		4,861,457		5,149,696		4,861,457		5,104,993
Other Commercial Real Estate | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,150	[3]	4,905	[3]	16,862	[3]	4,148	[3]
Charge-offs	(796)	[3]	(3,289)	[3]	(796)	[3]	(11,474)	[3]
Recoveries	0	[3]	91	[3]	0	[3]	91	[3]
Provisions	(1,160)	[3]	11,134	[3]	(6,872)	[3]	20,076	[3]
Ending balance	9,194	[3]	12,841	[3]	9,194	[3]	12,841	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	9,194	[3]	12,841	[3]	9,194	[3]	12,841	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	9,194	[3]	12,841	[3]	9,194	[3]	12,841	[3]	16,862	[3]
Loans and leases acquired with deteriorated credit quality	115,787		173,606		115,787		173,606		158,394
Other Commercial Real Estate | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,248		2,204		2,169		2,200
Charge-offs	(112)		0		(254)		(83)
Recoveries	0		(6)		0		(6)
Provisions	277		58		498		145
Ending balance	2,413		2,268		2,413		2,268
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	498		56		498		56		283
ALLL for loans and leases collectively evaluated for impairment	1,915		2,212		1,915		2,212		1,886
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	2,413		2,268		2,413		2,268
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	4,919		1,770		4,919		1,770		5,686
Loans and leases collectively evaluated for impairment	157,660		147,207		157,660		147,207		139,085
Net loans and leases	162,579		148,977		162,579		148,977		144,771
Commercial and Industrial | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,728	[3]	6,712	[3]	5,500	[3]	6,828	[3]
Charge-offs	(2,827)	[3]	(2,413)	[3]	(6,016)	[3]	(2,443)	[3]
Recoveries	0	[3]	12	[3]	0	[3]	12	[3]
Provisions	3,823	[3]	(2,439)	[3]	15,240	[3]	(2,525)	[3]
Ending balance	14,724	[3]	1,872	[3]	14,724	[3]	1,872	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	14,724	[3]	1,872	[3]	14,724	[3]	1,872	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	14,724	[3]	1,872	[3]	14,724	[3]	1,872	[3]	5,500	[3]
Loans and leases acquired with deteriorated credit quality	66,442		125,492		66,442		125,492		113,442
Commercial and Industrial | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	24,246		24,365		23,723		24,089
Charge-offs	(1,599)		(1,592)		(3,046)		(2,613)
Recoveries	(187)		(277)		(437)		(282)
Provisions	2,081		1,868		3,801		3,160
Ending balance	24,915		24,918		24,915		24,918
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	2,318		430		2,318		430		640
ALLL for loans and leases collectively evaluated for impairment	22,597		24,488		22,597		24,488		23,083
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	24,915		24,918		24,915		24,918
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	18,754		14,063		18,754		14,063		15,996
Loans and leases collectively evaluated for impairment	1,704,007		1,791,749		1,704,007		1,791,749		1,748,411
Net loans and leases	1,722,761		1,805,812		1,722,761		1,805,812		1,764,407
Lease Financing | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3	[3]	0	[3]	13	[3]	0	[3]
Charge-offs	0	[3]	0	[3]	0	[3]	0	[3]
Recoveries	0	[3]	0	[3]	0	[3]	0	[3]
Provisions	(3)	[3]	0	[3]	(13)	[3]	0	[3]
Ending balance	0	[3]	0	[3]	0	[3]	0	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	0	[3]	0	[3]	0	[3]	0	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	0	[3]	0	[3]	0	[3]	0	[3]	13	[3]
Loans and leases acquired with deteriorated credit quality	0		224		0		224		57
Lease Financing | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,320		3,369		3,288		3,384
Charge-offs	(144)		(252)		(335)		(252)
Recoveries	(18)		(37)		(48)		(37)
Provisions	321		204		514		189
Ending balance	3,515		3,358		3,515		3,358
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	70		48		70		48		17
ALLL for loans and leases collectively evaluated for impairment	3,445		3,310		3,445		3,310		3,271
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	3,515		3,358		3,515		3,358
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	354		617		354		617		328
Loans and leases collectively evaluated for impairment	320,349		302,487		320,349		302,487		312,541
Net loans and leases	320,703		303,104		320,703		303,104		312,869
Other | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,281		1,419		1,315		1,473
Charge-offs	(28)		0		(28)		0
Recoveries	0		0		(4)		0
Provisions	(70)		(68)		(108)		(122)
Ending balance	1,183		1,351		1,183		1,351
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0		0		0		0		14
ALLL for loans and leases collectively evaluated for impairment	1,183		1,351		1,183		1,351		1,301
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	1,183		1,351		1,183		1,351
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	742		0		742		0		193
Loans and leases collectively evaluated for impairment	139,996		170,758		139,996		170,758		158,176
Net loans and leases	140,738		170,758		140,738		170,758		158,369
Residential Mortgage | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,732	[3]	1,012	[3]	5,433	[3]	113	[3]
Charge-offs	(657)	[3]	(1,927)	[3]	(2,612)	[3]	(2,734)	[3]
Recoveries	142	[3]	44	[3]	142	[3]	44	[3]
Provisions	1,358	[3]	4,524	[3]	2,612	[3]	6,230	[3]
Ending balance	5,575	[3]	3,653	[3]	5,575	[3]	3,653	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	5,575	[3]	3,653	[3]	5,575	[3]	3,653	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	5,575	[3]	3,653	[3]	5,575	[3]	3,653	[3]	5,433	[3]
Loans and leases acquired with deteriorated credit quality	322,053		354,033		322,053		354,033		327,568
Residential Mortgage | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	9,107		7,129		8,879		7,009
Charge-offs	(1,255)		(713)		(2,290)		(719)
Recoveries	(269)		(3)		(312)		(4)
Provisions	(482)		985		738		1,110
Ending balance	7,639		7,404		7,639		7,404
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	1,451		455		1,451		455		411
ALLL for loans and leases collectively evaluated for impairment	6,188		6,949		6,188		6,949		8,468
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	7,639		7,404		7,639		7,404
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	19,305		11,102		19,305		11,102		9,776
Loans and leases collectively evaluated for impairment	789,925		814,508		789,925		814,508		774,342
Net loans and leases	809,230		825,610		809,230		825,610		784,118
Revolving Mortgage | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,027	[3]	1,451	[3]	77	[3]	676	[3]
Charge-offs	0	[3]	0	[3]	0	[3]	0	[3]
Recoveries	0	[3]	0	[3]	0	[3]	0	[3]
Provisions	1,521	[3]	(1,441)	[3]	2,471	[3]	(666)	[3]
Ending balance	2,548	[3]	10	[3]	2,548	[3]	10	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	2,548	[3]	10	[3]	2,548	[3]	10	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	2,548	[3]	10	[3]	2,548	[3]	10	[3]	77	[3]
Loans and leases acquired with deteriorated credit quality	37,110		11,933		37,110		11,933		51,552
Revolving Mortgage | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	26,911		19,363		27,045		18,016
Charge-offs	(3,331)		(4,404)		(6,271)		(4,446)
Recoveries	(198)		(159)		(414)		(159)
Provisions	2,922		6,902		5,512		8,291
Ending balance	26,700		22,020		26,700		22,020
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	51		0		51		0		0
ALLL for loans and leases collectively evaluated for impairment	26,649		22,020		26,649		22,020		27,045
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	26,700		22,020		26,700		22,020
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	3,594		0		3,594		0		0
Loans and leases collectively evaluated for impairment	2,264,616		2,303,687		2,264,616		2,303,687		2,296,306
Net loans and leases	2,268,210		2,303,687		2,268,210		2,303,687		2,296,306
Construction and Land Development - Non - Commercial | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,720	[3]	5,468	[3]	4,652	[3]	5,607	[3]
Charge-offs	(9)	[3]	(2,276)	[3]	(9)	[3]	(5,044)	[3]
Recoveries	0	[3]	0	[3]	0	[3]	0	[3]
Provisions	1,069	[3]	1,528	[3]	(863)	[3]	4,157	[3]
Ending balance	3,780	[3]	4,720	[3]	3,780	[3]	4,720	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	3,780	[3]	4,720	[3]	3,780	[3]	4,720	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	3,780	[3]	4,720	[3]	3,780	[3]	4,720	[3]	4,652	[3]
Loans and leases acquired with deteriorated credit quality	39,294		82,177		39,294		82,177		105,536
Construction and Land Development - Non - Commercial | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,397		1,328		1,427		1,751
Charge-offs	0		(363)		(675)		(373)
Recoveries	(145)		(70)		(152)		(73)
Provisions	273		289		911		(127)
Ending balance	1,815		1,324		1,815		1,324
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	205		93		205		93		145
ALLL for loans and leases collectively evaluated for impairment	1,610		1,231		1,610		1,231		1,282
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	1,815		1,324		1,815		1,324
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	3,458		2,562		3,458		2,562		3,676
Loans and leases collectively evaluated for impairment	124,268		142,883		124,268		142,883		133,595
Net loans and leases	127,726		145,445		127,726		145,445		137,271
Consumer | Covered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	277	[3]	13	[3]	474	[3]	23	[3]
Charge-offs	(30)	[3]	(74)	[3]	(35)	[3]	(74)	[3]
Recoveries	0	[3]	0	[3]	0	[3]	0	[3]
Provisions	(245)	[3]	73	[3]	(437)	[3]	63	[3]
Ending balance	2	[3]	12	[3]	2	[3]	12	[3]
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	2	[3]	12	[3]	2	[3]	12	[3]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	2	[3]	12	[3]	2	[3]	12	[3]	474	[3]
Loans and leases acquired with deteriorated credit quality	3,543		5,848		3,543		5,848		6,141
Consumer | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	24,288		27,778		25,962		29,448
Charge-offs	(2,277)		(3,221)		(5,285)		(9,289)
Recoveries	(497)		(433)		(929)		(433)
Provisions	2,480		2,089		3,382		6,487
Ending balance	24,988		27,079		24,988		27,079
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	253		45		253		45		47
ALLL for loans and leases collectively evaluated for impairment	24,735		27,034		24,735		27,034		25,915
Non-specific ALLL	0		0		0		0		0
Total allowance for loan and lease losses	24,988		27,079		24,988		27,079
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	3,108		994		3,108		994		992
Loans and leases collectively evaluated for impairment	428,556		555,876		428,556		555,876		496,378
Net loans and leases	431,664		556,870		431,664		556,870		497,370
Non-Specific | Noncovered Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	14,822		14,095		14,122		13,863
Charge-offs	0		0		0		0
Recoveries	0		0		0		0
Provisions	1,120		(17)		1,820		215
Ending balance	15,942		14,078		15,942		14,078
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0		0		0		0		0
ALLL for loans and leases collectively evaluated for impairment	0		0		0		0		0
Non-specific ALLL	15,942		14,078		15,942		14,078		14,122
Total allowance for loan and lease losses	15,942		14,078		15,942		14,078
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	0		0		0		0		0
Loans and leases collectively evaluated for impairment	0		0		0		0		0
Net loans and leases	0		0		0		0		0
Pooled Loans
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
Allowance for loan and lease losses	$ 19,157				$ 19,157				$ 1,099

[1] Unaudited

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

[3] The allowance of $19,157 at June 30, 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.