Loans and Leases (Composition of the Loans and Leases Outstanding By Credit Quality Indicator) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012		Jun. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	$ 1,443,336	[1]	$ 1,809,235	[2]	$ 1,999,351	[1]
Originated	11,655,469	[2]	11,576,115	[2]	11,462,458	[2]
Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,140,029		1,450,035		1,598,579
Originated	8,140,071		7,994,495		7,825,628
Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	303,307		359,200		400,772
Originated	3,515,398		3,581,620		3,636,830
Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	160,733		237,906		272,445
Originated	305,789		309,190		329,151
Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	9,009		20,793		39,294
Originated	119,253		131,992		127,726
Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	859,038		1,054,473		1,142,677
Originated	6,135,068		6,029,435		5,883,116
Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	81,904		107,119		115,787
Originated	176,031		160,980		162,579
Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	37,336		49,463		66,442
Originated	997,504		1,038,530		989,341
Lease Financing | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	352,818		330,679		320,703
Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,018		1,074		1,228
Originated	172,861		125,681		140,738
Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	256,972		297,926		322,053
Originated	884,020		822,889		809,230
Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	36,153		38,710		37,110
Originated	2,123,814		2,210,133		2,268,210
Consumer | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,173		1,771		2,315
Originated	388,311		416,606		431,664
Pass | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	7,678,075		7,459,277		7,215,759
Pass | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	283,342		274,480		289,974
Pass | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	5,833,551		5,688,541		5,488,595
Pass | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	170,071		151,549		149,977
Pass | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	874,336		894,998		832,372
Pass | Lease Financing | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	345,443		325,626		315,119
Pass | Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	171,332		124,083		139,722
Special Mention | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	159,084		200,073		264,087
Special Mention | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	12,567		14,666		10,353
Special Mention | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	132,787		166,882		227,233
Special Mention | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	1,529		2,812		6,220
Special Mention | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	8,047		13,275		17,284
Special Mention | Lease Financing | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	2,625		1,601		2,740
Special Mention | Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	1,529		837		257
Substandard | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	187,666		196,257		197,611
Substandard | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	9,827		18,761		27,266
Substandard | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	157,689		157,966		146,806
Substandard | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	4,125		5,038		5,821
Substandard | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	12,025		12,073		15,109
Substandard | Lease Financing | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	4,000		1,663		1,867
Substandard | Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	0		756		742
Doubtful | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	12,087		16,336		17,131
Doubtful | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	53		952		1,232
Doubtful | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	9,048		13,475		13,660
Doubtful | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	80		98		265
Doubtful | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	2,156		1,040		1,457
Doubtful | Lease Financing | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	750		771		517
Doubtful | Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	0		0		0
Ungraded | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	103,159		122,552		131,040
Ungraded | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	0		331		326
Ungraded | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	1,993		2,571		6,822
Ungraded | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	226		1,483		296
Ungraded | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	100,940		117,144		123,119
Ungraded | Lease Financing | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	0		1,018		460
Ungraded | Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	0		5		17
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,443,336		1,809,235		1,999,351
Acquired Loans | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	160,733		237,906		272,445
Acquired Loans | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	9,009		20,793		39,294
Acquired Loans | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	859,038		1,054,473		1,142,677
Acquired Loans | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	81,904		107,119		115,787
Acquired Loans | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	37,336		49,463		66,442
Acquired Loans | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	256,972		297,926		322,053
Acquired Loans | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	36,153		38,710		37,110
Acquired Loans | Consumer and Other | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	2,191		2,845		3,543
Acquired Loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	556,606		650,661		658,299
Acquired Loans | Pass | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	7,420		17,010		20,662
Acquired Loans | Pass | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	239		334		137
Acquired Loans | Pass | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	325,651		376,974		358,287
Acquired Loans | Pass | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	27,159		33,570		36,459
Acquired Loans | Pass | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	13,304		19,451		25,280
Acquired Loans | Pass | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	155,204		172,165		187,317
Acquired Loans | Pass | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	26,156		29,540		28,528
Acquired Loans | Pass | Consumer and Other | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,473		1,617		1,629
Acquired Loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	253,046		331,614		472,953
Acquired Loans | Special Mention | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	23,189		25,734		79,987
Acquired Loans | Special Mention | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		0		2,428
Acquired Loans | Special Mention | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	197,890		259,264		331,659
Acquired Loans | Special Mention | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	6,472		17,518		23,293
Acquired Loans | Special Mention | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	11,446		12,465		16,969
Acquired Loans | Special Mention | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	12,073		14,863		16,602
Acquired Loans | Special Mention | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,951		1,736		1,748
Acquired Loans | Special Mention | Consumer and Other | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	25		34		267
Acquired Loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	475,764		616,692		624,774
Acquired Loans | Substandard | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	71,631		105,061		73,179
Acquired Loans | Substandard | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	7,476		17,190		30,190
Acquired Loans | Substandard | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	272,830		344,542		372,528
Acquired Loans | Substandard | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	41,314		44,335		46,465
Acquired Loans | Substandard | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	6,860		14,698		15,630
Acquired Loans | Substandard | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	67,769		83,193		79,239
Acquired Loans | Substandard | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	7,644		7,434		6,834
Acquired Loans | Substandard | Consumer and Other | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	240		239		709
Acquired Loans | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	135,559		182,568		213,846
Acquired Loans | Doubtful | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	56,566		87,445		95,354
Acquired Loans | Doubtful | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,294		3,269		6,539
Acquired Loans | Doubtful | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	62,006		73,016		77,679
Acquired Loans | Doubtful | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	6,959		11,696		9,570
Acquired Loans | Doubtful | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	5,500		2,757		8,449
Acquired Loans | Doubtful | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	2,832		4,268		15,702
Acquired Loans | Doubtful | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	402		0		0
Acquired Loans | Doubtful | Consumer and Other | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		117		553
Acquired Loans | Ungraded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	22,361		27,700		29,479
Acquired Loans | Ungraded | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,927		2,656		3,263
Acquired Loans | Ungraded | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		0		0
Acquired Loans | Ungraded | Commercial Mortgage | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	661		677		2,524
Acquired Loans | Ungraded | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		0		0
Acquired Loans | Ungraded | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	226		92		114
Acquired Loans | Ungraded | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	19,094		23,437		23,193
Acquired Loans | Ungraded | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		0		0
Acquired Loans | Ungraded | Consumer and Other | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	453		838		385
Originated Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	11,655,469		11,576,115		11,462,458
Originated Loans | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	3,515,398		3,581,620		3,636,830
Originated Loans | Construction and Land Development | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	305,789		309,190		329,151
Originated Loans | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	119,253		131,992		127,726
Originated Loans | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	6,135,068		6,029,435		5,883,116
Originated Loans | Other Commercial Real Estate | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	176,031		160,980		162,579
Originated Loans | Commercial and Industrial | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	997,504		1,038,530		989,341
Originated Loans | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	352,818		330,679		320,703
Originated Loans | Other | Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	172,861		125,681		140,738
Originated Loans | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	884,020		822,889		809,230
Originated Loans | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	2,123,814		2,210,133		2,268,210
Originated Loans | Consumer | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	388,311		416,606		431,664
Originated Loans | Current | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	3,467,430		3,514,794		3,585,379
Originated Loans | Current | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	117,618		128,764		125,096
Originated Loans | Current | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	854,345		786,626		781,632
Originated Loans | Current | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	2,110,414		2,190,186		2,251,428
Originated Loans | Current | Consumer | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	385,053		409,218		427,223
Originated Loans | 30 to 59 Days Past Due | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	24,617		34,925		26,077
Originated Loans | 30 to 59 Days Past Due | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	630		1,941		1,352
Originated Loans | 30 to 59 Days Past Due | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	14,626		15,711		12,601
Originated Loans | 30 to 59 Days Past Due | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	7,587		12,868		10,131
Originated Loans | 30 to 59 Days Past Due | Consumer | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	1,774		4,405		1,993
Originated Loans | 60 to 89 Days Past Due | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	5,416		12,954		7,541
Originated Loans | 60 to 89 Days Past Due | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	8		490		447
Originated Loans | 60 to 89 Days Past Due | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	2,427		7,559		3,659
Originated Loans | 60 to 89 Days Past Due | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	2,134		3,200		2,460
Originated Loans | 60 to 89 Days Past Due | Consumer | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	847		1,705		975
Originated Loans | 90 Days or Greater Past Due | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	17,935		18,947		17,833
Originated Loans | 90 Days or Greater Past Due | Construction and Land Development | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	997		797		831
Originated Loans | 90 Days or Greater Past Due | Residential Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	12,622		12,993		11,338
Originated Loans | 90 Days or Greater Past Due | Revolving Mortgage | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	3,679		3,879		4,191
Originated Loans | 90 Days or Greater Past Due | Consumer | Non-Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originated	$ 637		$ 1,278		$ 1,473

[1] Unaudited

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