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, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification					$ 7,368		$ 0
Loans and Leases Evaluated for Impairment [Abstract]
Net loans and leases	12,840,489	[1]	13,188,880	[1]	12,840,489	[1]	13,188,880	[1]	13,066,332	[2]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
Allowance for loan and lease losses	258,316	[1]	272,929	[1]	258,316	[1]	272,929	[1]	319,018	[2]
Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	7,368	[3]			7,368	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	176,546		186,383		179,046		180,883
Charge-offs	(6,494)		(13,794)		(14,561)		(31,425)
Recoveries	2,131		1,554		3,682		3,573
Provisions	2,231		10,989		6,247		32,101
Ending balance	181,782		185,132		181,782		185,132
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	14,582		16,212		14,582		16,212		18,355
ALLL for loans and leases collectively evaluated for impairment	167,200		152,978		167,200		152,978		144,841
Non-specific ALLL			15,942				15,942		15,850
Total allowance for loan and lease losses	181,782		185,132		181,782		185,132
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	177,616		221,699		177,616		221,699		202,253
Loans and leases collectively evaluated for impairment	11,477,853		11,240,759		11,477,853		11,240,759		11,373,862
Net loans and leases	11,655,469		11,462,458		11,655,469		11,462,458		11,576,115
Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	96,473		86,117		139,972		89,261
Charge-offs	(4,466)		(17,140)		(25,343)		(29,887)
Recoveries	0		142		0		142
Provisions	(15,473)		18,678		(38,095)		28,281
Ending balance	76,534		87,797		76,534		87,797
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	76,534		87,797		76,534		87,797
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	76,534		87,797		76,534		87,797		139,972
Loans and leases acquired with deteriorated credit quality	1,443,336		1,999,351		1,443,336		1,999,351		1,809,235
Construction and Land Development - Commercial | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	5,141	[3]			5,141	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,311		6,608		6,031		5,467
Charge-offs	(1,286)		(3,492)		(1,540)		(9,221)
Recoveries	270		228		638		269
Provisions	3,296		1,712		1,462		8,541
Ending balance	11,732		5,056		11,732		5,056
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	977		1,621		977		1,621		2,469
ALLL for loans and leases collectively evaluated for impairment	10,755		3,435		10,755		3,435		3,562
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	11,732		5,056		11,732		5,056
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	8,921		28,230		8,921		28,230		17,075
Loans and leases collectively evaluated for impairment	296,868		300,921		296,868		300,921		292,115
Net loans and leases	305,789		329,151		305,789		329,151		309,190
Construction and Land Development - Commercial | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,306		12,736		31,186		16,693
Charge-offs	(626)		(3,639)		(5,359)		(5,026)
Recoveries	0		0		0		0
Provisions	(5,091)		6,886		(18,238)		4,316
Ending balance	7,589		15,983		7,589		15,983
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	7,589		15,983		7,589		15,983
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	7,589		15,983		7,589		15,983		31,186
Loans and leases acquired with deteriorated credit quality	160,733		272,445		160,733		272,445		237,906
Commercial Mortgage | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	27,421	[3]			27,421	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	82,119		72,155		80,229		67,486
Charge-offs	(213)		(1,556)		(869)		(4,020)
Recoveries	491		12		499		1,008
Provisions	(4,976)		10,962		(2,438)		17,099
Ending balance	104,842		81,573		104,842		81,573
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	8,687		9,745		8,687		9,745		11,697
ALLL for loans and leases collectively evaluated for impairment	96,155		71,828		96,155		71,828		68,532
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	104,842		81,573		104,842		81,573
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	127,628		139,235		127,628		139,235		133,804
Loans and leases collectively evaluated for impairment	6,007,440		5,743,881		6,007,440		5,743,881		5,895,631
Net loans and leases	6,135,068		5,883,116		6,135,068		5,883,116		6,029,435
Commercial Mortgage | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	38,293		39,744		50,275		39,557
Charge-offs	(2,183)		(9,182)		(12,081)		(15,393)
Recoveries	0		0		0		0
Provisions	(2,522)		5,429		(4,606)		11,827
Ending balance	33,588		35,991		33,588		35,991
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	33,588		35,991		33,588		35,991
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	33,588		35,991		33,588		35,991		50,275
Loans and leases acquired with deteriorated credit quality	859,038		1,142,677		859,038		1,142,677		1,054,473
Other Commercial Real Estate | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(815)	[3]			(815)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,915		2,248		2,059		2,169
Charge-offs	(18)		(112)		(72)		(254)
Recoveries	26		0		36		0
Provisions	(51)		277		(151)		498
Ending balance	1,057		2,413		1,057		2,413
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	115		498		115		498		298
ALLL for loans and leases collectively evaluated for impairment	942		1,915		942		1,915		1,761
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	1,057		2,413		1,057		2,413
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	2,887		4,919		2,887		4,919		3,375
Loans and leases collectively evaluated for impairment	173,144		157,660		173,144		157,660		157,605
Net loans and leases	176,031		162,579		176,031		162,579		160,980
Other Commercial Real Estate | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,172		11,150		11,234		16,862
Charge-offs	0		(796)		(931)		(796)
Recoveries	0		0		0		0
Provisions	(576)		(1,160)		(5,707)		(6,872)
Ending balance	4,596		9,194		4,596		9,194
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	4,596		9,194		4,596		9,194
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	4,596		9,194		4,596		9,194		11,234
Loans and leases acquired with deteriorated credit quality	81,904		115,787		81,904		115,787		107,119
Commercial and Industrial | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	7,551	[3]			7,551	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,661		24,246		14,050		23,723
Charge-offs	(988)		(1,599)		(2,246)		(3,046)
Recoveries	288		187		657		437
Provisions	(1,203)		(8,526)		(703)		(6,806)
Ending balance	19,309		14,308		19,309		14,308
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	2,286		2,318		2,286		2,318		2,133
ALLL for loans and leases collectively evaluated for impairment	17,023		11,990		17,023		11,990		11,917
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	19,309		14,308		19,309		14,308
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	12,004		18,754		12,004		18,754		22,619
Loans and leases collectively evaluated for impairment	985,500		970,587		985,500		970,587		1,015,911
Net loans and leases	997,504		989,341		997,504		989,341		1,038,530
Commercial and Industrial | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,876		13,728		8,897		5,500
Charge-offs	(1,004)		(2,827)		(2,257)		(6,016)
Recoveries	0		0		0		0
Provisions	(4,936)		3,823		(704)		15,240
Ending balance	5,936		14,724		5,936		14,724
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	5,936		14,724		5,936		14,724
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	5,936		14,724		5,936		14,724		8,897
Loans and leases acquired with deteriorated credit quality	37,336		66,442		37,336		66,442		49,463
Lease Financing | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(253)	[3]			(253)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,543		3,320		3,521		3,288
Charge-offs	(92)		(144)		(92)		(335)
Recoveries	19		18		19		48
Provisions	1,775		321		1,797		514
Ending balance	4,992		3,515		4,992		3,515
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	376		70		376		70		202
ALLL for loans and leases collectively evaluated for impairment	4,616		3,445		4,616		3,445		3,319
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	4,992		3,515		4,992		3,515
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	724		354		724		354		804
Loans and leases collectively evaluated for impairment	352,094		320,349		352,094		320,349		329,875
Net loans and leases	352,818		320,703		352,818		320,703		330,679
Lease Financing | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0		3		0		13
Charge-offs	0		0		0		0
Recoveries	0		0		0		0
Provisions	0		(3)		0		(13)
Ending balance	0		0		0		0
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	0		0		0		0
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	0		0		0		0		0
Loans and leases acquired with deteriorated credit quality	0		0		0		0		0
Other | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(1,288)	[3]			(1,288)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,490		1,281		1,175		1,315
Charge-offs	0		(28)		(6)		(28)
Recoveries	3		0		3		4
Provisions	155		(70)		476		(108)
Ending balance	360		1,183		360		1,183
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0		0		0		0		53
ALLL for loans and leases collectively evaluated for impairment	360		1,183		360		1,183		1,122
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	360		1,183		360		1,183
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	0		742		0		742		707
Loans and leases collectively evaluated for impairment	172,861		139,996		172,861		139,996		124,974
Net loans and leases	172,861		140,738		172,861		140,738		125,681
Residential Mortgage | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	5,717	[3]			5,717	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,790		9,107		3,836		8,879
Charge-offs	(450)		(1,255)		(1,268)		(2,290)
Recoveries	61		269		100		312
Provisions	878		(482)		1,611		738
Ending balance	9,996		7,639		9,996		7,639
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	1,073		1,451		1,073		1,451		959
ALLL for loans and leases collectively evaluated for impairment	8,923		6,188		8,923		6,188		2,877
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	9,996		7,639		9,996		7,639
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	16,151		19,305		16,151		19,305		15,836
Loans and leases collectively evaluated for impairment	867,869		789,925		867,869		789,925		807,053
Net loans and leases	884,020		809,230		884,020		809,230		822,889
Residential Mortgage | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	17,603		4,732		19,837		5,433
Charge-offs	(386)		(657)		(1,115)		(2,612)
Recoveries	0		142		0		142
Provisions	55		1,358		(1,450)		2,612
Ending balance	17,272		5,575		17,272		5,575
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	17,272		5,575		17,272		5,575
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	17,272		5,575		17,272		5,575		19,837
Loans and leases acquired with deteriorated credit quality	256,972		322,053		256,972		322,053		297,926
Revolving Mortgage | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(9,838)	[3]			(9,838)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	24,499		26,911		25,185		27,045
Charge-offs	(878)		(3,331)		(3,066)		(6,271)
Recoveries	307		198		378		414
Provisions	907		2,922		2,338		5,512
Ending balance	14,997		26,700		14,997		26,700
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	895		51		895		51		1
ALLL for loans and leases collectively evaluated for impairment	14,102		26,649		14,102		26,649		25,184
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	14,997		26,700		14,997		26,700
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	6,972		3,594		6,972		3,594		4,203
Loans and leases collectively evaluated for impairment	2,116,842		2,264,616		2,116,842		2,264,616		2,205,930
Net loans and leases	2,123,814		2,268,210		2,123,814		2,268,210		2,210,133
Revolving Mortgage | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,135		1,027		9,754		77
Charge-offs	(235)		0		(350)		0
Recoveries	0		0		0		0
Provisions	(869)		1,521		(3,373)		2,471
Ending balance	6,031		2,548		6,031		2,548
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	6,031		2,548		6,031		2,548
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	6,031		2,548		6,031		2,548		9,754
Loans and leases acquired with deteriorated credit quality	36,153		37,110		36,153		37,110		38,710
Construction and Land Development - Noncommercial | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(478)	[3]			(478)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,419		1,397		1,721		1,427
Charge-offs	0		0		(245)		(675)
Recoveries	23		145		79		152
Provisions	(244)		273		(357)		911
Ending balance	720		1,815		720		1,815
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	41		205		41		205		287
ALLL for loans and leases collectively evaluated for impairment	679		1,610		679		1,610		1,434
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	720		1,815		720		1,815
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	910		3,458		910		3,458		1,321
Loans and leases collectively evaluated for impairment	118,343		124,268		118,343		124,268		130,671
Net loans and leases	119,253		127,726		119,253		127,726		131,992
Construction and Land Development - Noncommercial | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,756		2,720		8,287		4,652
Charge-offs	0		(9)		(3,218)		(9)
Recoveries	0		0		0		0
Provisions	(1,524)		1,069		(3,837)		(863)
Ending balance	1,232		3,780		1,232		3,780
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	1,232		3,780		1,232		3,780
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	1,232		3,780		1,232		3,780		8,287
Loans and leases acquired with deteriorated credit quality	9,009		39,294		9,009		39,294		20,793
Consumer | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(10,018)	[3]			(10,018)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	24,027		24,288		25,389		25,962
Charge-offs	(2,569)		(2,277)		(5,157)		(5,285)
Recoveries	643		497		1,273		929
Provisions	1,694		2,480		2,290		3,382
Ending balance	13,777		24,988		13,777		24,988
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	132		253		132		253		256
ALLL for loans and leases collectively evaluated for impairment	13,645		24,735		13,645		24,735		25,133
Non-specific ALLL			0				0		0
Total allowance for loan and lease losses	13,777		24,988		13,777		24,988
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	1,419		3,108		1,419		3,108		2,509
Loans and leases collectively evaluated for impairment	386,892		428,556		386,892		428,556		414,097
Net loans and leases	388,311		431,664		388,311		431,664		416,606
Consumer | Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	332		277		502		474
Charge-offs	(32)		(30)		(32)		(35)
Recoveries	0		0		0		0
Provisions	(10)		(245)		(180)		(437)
Ending balance	290		2		290		2
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	290		2		290		2
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	290		2		290		2		502
Loans and leases acquired with deteriorated credit quality	2,191		3,543		2,191		3,543		2,845
Non-Specific | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Reclassification	(15,772)	[3]			(15,772)	[3]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	15,772		14,822		15,850		14,122
Charge-offs	0		0		0		0
Recoveries	0		0		0		0
Provisions	0		1,120		(78)		1,820
Ending balance	0		15,942		0		15,942
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				15,942		15,850
Total allowance for loan and lease losses	0		15,942		0		15,942
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

[1] Unaudited

[2] Derived from 2012 Annual Report on Form 10-K.

[3] (1) Reclassification results from enhancements to the ALLL calculation during the second quarter of 2013 that resulted in the allocation of $15,772 previously designated as 'non-specific' to other loan classes and the absorption of $7,368 of the reserve for unfunded commitments related to unfunded, revocable loan commitments into the ALLL. Further discussion is contained in Note A.