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			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Allowance for Loan and Lease Losses [Roll Forward]
Reclassification				$ 7,368		$ 0
Loans and Leases Evaluated for Impairment [Abstract]
Net loans and leases	12,835,067	[1]		12,835,067	[1]		13,066,332	[2]
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
Allowance for loan and lease losses	237,799	[1]		237,799	[1]		319,018	[2]
Noncommerical
Allowance for Loan and Lease Losses [Roll Forward]
Reclassification				7,368	[3]
Noncommerical | Non-specific
Allowance for Loan and Lease Losses [Roll Forward]
Reclassification				(15,772)	[3]
Originated Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	181,782		185,132	179,046		180,883
Reclassification	0	[3]		7,368	[3]
Charge-offs	(10,226)		(7,680)	(24,787)		(39,105)
Recoveries	1,794		1,198	5,476		4,769
Provisions	4,932		7,397	11,179		39,500
Ending balance	178,282		186,047	178,282		186,047
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	14,216			14,216			18,355
ALLL for loans and leases collectively evaluated for impairment	164,066			164,066			144,841
Non-specific ALLL							15,850
Total allowance for loan and lease losses	178,282		186,047	178,282		186,047
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	155,916			155,916			202,253
Loans and leases collectively evaluated for impairment	11,728,669			11,728,669			11,373,862
Net loans and leases	11,884,585			11,884,585			11,576,115
Originated Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,732		5,056	6,031		5,467
Reclassification	0	[3]		5,141	[3]
Charge-offs	(3,030)		(283)	(4,570)		(9,504)
Recoveries	84		101	722		370
Provisions	1,797		1,593	3,259		10,134
Ending balance	10,583		6,467	10,583		6,467
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	435			435			2,469
ALLL for loans and leases collectively evaluated for impairment	10,148			10,148			3,562
Non-specific ALLL							0
Total allowance for loan and lease losses	10,583		6,467	10,583		6,467
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	2,290			2,290			17,075
Loans and leases collectively evaluated for impairment	297,976			297,976			292,115
Net loans and leases	300,266			300,266			309,190
Originated Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	104,842		81,573	80,229		67,486
Reclassification	0	[3]		27,421	[3]
Charge-offs	(794)		(1,428)	(1,662)		(5,448)
Recoveries	241		222	740		1,230
Provisions	(5,256)		1,069	(7,695)		18,168
Ending balance	99,033		81,436	99,033		81,436
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	8,506			8,506			11,697
ALLL for loans and leases collectively evaluated for impairment	90,527			90,527			68,532
Non-specific ALLL							0
Total allowance for loan and lease losses	99,033		81,436	99,033		81,436
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	116,222			116,222			133,804
Loans and leases collectively evaluated for impairment	6,191,970			6,191,970			5,895,631
Net loans and leases	6,308,192			6,308,192			6,029,435
Originated Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,057		2,413	2,059		2,169
Reclassification	0	[3]		(815)	[3]
Charge-offs	(5)		0	(77)		(254)
Recoveries	39		6	75		6
Provisions	(56)		(180)	(207)		318
Ending balance	1,035		2,239	1,035		2,239
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	133			133			298
ALLL for loans and leases collectively evaluated for impairment	902			902			1,761
Non-specific ALLL							0
Total allowance for loan and lease losses	1,035		2,239	1,035		2,239
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	2,835			2,835			3,375
Loans and leases collectively evaluated for impairment	174,764			174,764			157,605
Net loans and leases	177,599			177,599			160,980
Originated Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	19,309		14,308	14,050		23,723
Reclassification	0	[3]		7,551	[3]
Charge-offs	(1,671)		(720)	(3,917)		(3,766)
Recoveries	344		179	1,003		616
Provisions	4,656		(131)	3,951		(6,937)
Ending balance	22,638		13,636	22,638		13,636
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	2,500			2,500			2,133
ALLL for loans and leases collectively evaluated for impairment	20,138			20,138			11,917
Non-specific ALLL							0
Total allowance for loan and lease losses	22,638		13,636	22,638		13,636
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	11,282			11,282			22,619
Loans and leases collectively evaluated for impairment	998,359			998,359			1,015,911
Net loans and leases	1,009,641			1,009,641			1,038,530
Originated Loans | Commercial | Lease financing
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,992		3,515	3,521		3,288
Reclassification	0	[3]		(253)	[3]
Charge-offs	(31)		0	(123)		(335)
Recoveries	71		27	90		75
Provisions	(439)		(95)	1,358		419
Ending balance	4,593		3,447	4,593		3,447
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	177			177			202
ALLL for loans and leases collectively evaluated for impairment	4,416			4,416			3,319
Non-specific ALLL							0
Total allowance for loan and lease losses	4,593		3,447	4,593		3,447
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	309			309			804
Loans and leases collectively evaluated for impairment	365,658			365,658			329,875
Net loans and leases	365,967			365,967			330,679
Originated Loans | Commercial | Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	360		1,183	1,175		1,315
Reclassification	0	[3]		(1,288)	[3]
Charge-offs	0		0	(6)		(28)
Recoveries	0		0	1		4
Provisions	(171)		(7)	307		(115)
Ending balance	189		1,176	189		1,176
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	0			0			53
ALLL for loans and leases collectively evaluated for impairment	189			189			1,122
Non-specific ALLL							0
Total allowance for loan and lease losses	189		1,176	189		1,176
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	0			0			707
Loans and leases collectively evaluated for impairment	180,435			180,435			124,974
Net loans and leases	180,435			180,435			125,681
Originated Loans | Noncommerical | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	9,996		7,639	3,836		8,879
Reclassification	0	[3]		5,717	[3]
Charge-offs	(719)		(1,090)	(1,987)		(3,381)
Recoveries	253		121	353		433
Provisions	515		516	2,126		1,255
Ending balance	10,045		7,186	10,045		7,186
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	1,113			1,113			959
ALLL for loans and leases collectively evaluated for impairment	8,932			8,932			2,877
Non-specific ALLL							0
Total allowance for loan and lease losses	10,045		7,186	10,045		7,186
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	14,333			14,333			15,836
Loans and leases collectively evaluated for impairment	913,093			913,093			807,053
Net loans and leases	927,426			927,426			822,889
Originated Loans | Noncommerical | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	720		1,815	1,721		1,427
Reclassification	0	[3]		(478)	[3]
Charge-offs	(59)		(239)	(304)		(914)
Recoveries	101		16	180		168
Provisions	(214)		530	(571)		1,441
Ending balance	548		2,122	548		2,122
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	52			52			287
ALLL for loans and leases collectively evaluated for impairment	496			496			1,434
Non-specific ALLL							0
Total allowance for loan and lease losses	548		2,122	548		2,122
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	938			938			1,321
Loans and leases collectively evaluated for impairment	120,615			120,615			130,671
Net loans and leases	121,553			121,553			131,992
Originated Loans | Noncommerical | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	14,997		26,700	25,185		27,045
Reclassification	0	[3]		(9,838)	[3]
Charge-offs	(1,472)		(1,613)	(4,540)		(7,885)
Recoveries	84		87	462		501
Provisions	2,206		1,213	4,546		6,726
Ending balance	15,815		26,387	15,815		26,387
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	1,167			1,167			1
ALLL for loans and leases collectively evaluated for impairment	14,648			14,648			25,184
Non-specific ALLL							0
Total allowance for loan and lease losses	15,815		26,387	15,815		26,387
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	6,495			6,495			4,203
Loans and leases collectively evaluated for impairment	2,106,745			2,106,745			2,205,930
Net loans and leases	2,113,240			2,113,240			2,210,133
Originated Loans | Noncommerical | Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,777		24,988	25,389		25,962
Reclassification	0	[3]		(10,018)	[3]
Charge-offs	(2,445)		(2,307)	(7,601)		(7,590)
Recoveries	577		439	1,850		1,366
Provisions	1,894		3,562	4,183		6,944
Ending balance	13,803		26,682	13,803		26,682
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment	133			133			256
ALLL for loans and leases collectively evaluated for impairment	13,670			13,670			25,133
Non-specific ALLL							0
Total allowance for loan and lease losses	13,803		26,682	13,803		26,682
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment	1,212			1,212			2,509
Loans and leases collectively evaluated for impairment	379,054			379,054			414,097
Net loans and leases	380,266			380,266			416,606
Originated Loans | Noncommerical | Non-specific
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0		15,942	15,850		14,122
Reclassification	0	[3]		(15,772)	[3]
Charge-offs	0		0	0		0
Recoveries	0		0	0		0
Provisions	0		(673)	(78)		1,147
Ending balance	0		15,269	0		15,269
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							15,850
Total allowance for loan and lease losses	0		15,269	0		15,269
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
Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	76,534		87,797	139,972		89,261
Charge-offs	(4,402)		(7,516)	(29,745)		(37,401)
Recoveries	0		0	0		142
Provisions	(12,615)		10,226	(50,710)		38,505
Ending balance	59,517		90,507	59,517		90,507
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	59,517		90,507	59,517		90,507
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	59,517			59,517			139,972
Loans and leases acquired with deteriorated credit quality	1,188,281			1,188,281			1,809,235
Acquired Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,589		15,983	31,186		16,693
Charge-offs	(1,263)		(1,434)	(3,435)		(6,460)
Recoveries	0		0	0		0
Provisions	(3,707)		3,186	(25,132)		7,502
Ending balance	2,619		17,735	2,619		17,735
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	2,619		17,735	2,619		17,735
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	2,619			2,619			31,186
Loans and leases acquired with deteriorated credit quality	93,963			93,963			237,906
Acquired Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	33,588		35,991	50,275		39,557
Charge-offs	(2,324)		(3,006)	(10,146)		(18,396)
Recoveries	0		0	0		0
Provisions	(1,944)		8,159	(10,809)		19,983
Ending balance	29,320		41,144	29,320		41,144
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	29,320		41,144	29,320		41,144
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	29,320			29,320			50,275
Loans and leases acquired with deteriorated credit quality	744,349			744,349			1,054,473
Acquired Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,596		9,194	11,234		16,862
Charge-offs	0		(34)	(6,622)		(831)
Recoveries	0		0	0		0
Provisions	(2,673)		(4,606)	(2,689)		(11,477)
Ending balance	1,923		4,554	1,923		4,554
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	1,923		4,554	1,923		4,554
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	1,923			1,923			11,234
Loans and leases acquired with deteriorated credit quality	51,108			51,108			107,119
Acquired Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,936		14,724	8,897		5,500
Charge-offs	(89)		(1,901)	(5,190)		(7,916)
Recoveries	0		0	0		0
Provisions	(73)		(9,114)	2,067		6,125
Ending balance	5,774		3,709	5,774		3,709
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	5,774		3,709	5,774		3,709
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	5,774			5,774			8,897
Loans and leases acquired with deteriorated credit quality	24,448			24,448			49,463
Acquired Loans | Commercial | Lease financing
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0		0	0		13
Charge-offs	0		0	0		0
Recoveries	0		0	0		0
Provisions	0		0	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
Loans and leases acquired with deteriorated credit quality	0			0			0
Acquired Loans | Noncommerical | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	17,272		5,575	19,837		5,433
Charge-offs	(509)		(819)	(1,973)		(3,431)
Recoveries	0		0	0		142
Provisions	(2,445)		4,754	(3,546)		7,366
Ending balance	14,318		9,510	14,318		9,510
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	14,318		9,510	14,318		9,510
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	14,318			14,318			19,837
Loans and leases acquired with deteriorated credit quality	232,310			232,310			297,926
Acquired Loans | Noncommerical | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,232		3,780	8,287		4,652
Charge-offs	(217)		(292)	0		(301)
Recoveries	0		0	0		0
Provisions	(467)		3,440	(7,739)		2,577
Ending balance	548		6,928	548		6,928
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	548		6,928	548		6,928
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	548			548			8,287
Loans and leases acquired with deteriorated credit quality	5,337			5,337			20,793
Acquired Loans | Noncommerical | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	6,031		2,548	9,754		77
Charge-offs	0		0	0		0
Recoveries	0		0	0		0
Provisions	(1,195)		2,946	(4,918)		5,417
Ending balance	4,836		5,494	4,836		5,494
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	4,836		5,494	4,836		5,494
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	4,836			4,836			9,754
Loans and leases acquired with deteriorated credit quality	34,834			34,834			38,710
Acquired Loans | Noncommerical | Consumer and Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	290		2	502		474
Charge-offs	0		(30)	(2,379)		(66)
Recoveries	0		0	0		0
Provisions	(111)		1,461	2,056		1,025
Ending balance	179		1,433	179		1,433
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	179		1,433	179		1,433
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality	179			179			502
Loans and leases acquired with deteriorated credit quality	$ 1,932			$ 1,932			$ 2,845

[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.