Allowance for Loan and Lease Losses (Summary of Activity In Allowance for Loan and Lease Losses) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		$ 204,466	$ 233,394	$ 319,018
Reclassification		0	0	7,368	[1]
Provisions		20,664	640	(32,255)
Charge-offs		(28,348)	(37,770)	(68,026)
Recoveries		9,434	8,202	7,289
Net charge-offs		(18,914)	(29,568)	(60,737)
Ending balance		206,216	204,466	233,394
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		204,466	233,394	319,018		$ 206,216	$ 204,466	$ 233,394
Loans and Leases Evaluated for Impairment [Abstract]
Net Loans and Leases						20,033,774	18,564,999
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
ALLL for loans and leases acquired with deteriorated credit quality						206,216	204,466
PCI Loans						950,516	1,186,498	1,029,426
Commercial
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						593,614	726,123
Commercial | Construction and land development
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						33,880	78,079
Commercial | Mortgage
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						525,468	577,518
Commercial | Other commercial real estate
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						17,076	40,193
Commercial | Commercial and industrial
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						15,182	27,254
Commercial | Other
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						2,008	3,079
Commercial | Consumer and Other
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						2,008	3,079
Noncommercial
Allowance for Loan and Lease Losses [Roll Forward]
Reclassification		7,368
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						356,902	460,375
Noncommercial | Construction and land development
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						0	912
Noncommercial | Mortgage
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						302,158	382,340
Noncommercial | Revolving mortgage
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						52,471	74,109
Noncommercial | Consumer
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						2,273	3,014
Noncommercial | Non-specific
Allowance for Loan and Lease Losses [Roll Forward]
Reclassification		(15,772)
Non-PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		182,837	179,874	179,046
Reclassification	[1]			7,368
Provisions		22,937	15,260	19,289
Charge-offs		(25,304)	(20,499)	(33,118)
Recoveries		9,434	8,202	7,289
Net charge-offs		(15,870)	(12,297)	(25,829)
Ending balance		189,904	182,837	179,874
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						7,200	15,717
ALLL for loans and leases collectively evaluated for impairment						182,704	167,120
Total allowance for loan and lease losses		182,837	179,874	179,046		189,904	182,837	179,874
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						150,367	119,593
Loans and leases collectively evaluated for impairment						19,139,107	17,463,074
Net Loans and Leases						19,289,474	17,582,667
Non-PCI Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		11,961	10,335	6,031
Reclassification	[1]			5,141
Provisions		4,773	1,735	2,809
Charge-offs		(1,012)	(316)	(4,685)
Recoveries		566	207	1,039
Ending balance		16,288	11,961	10,335
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						123	92
ALLL for loans and leases collectively evaluated for impairment						16,165	11,869
Total allowance for loan and lease losses		11,961	10,335	6,031		16,288	11,961	10,335
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						3,094	1,620
Loans and leases collectively evaluated for impairment						617,258	491,513
Net Loans and Leases						620,352	493,133
Non-PCI Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		85,189	100,257	80,229
Reclassification	[1]			27,421
Provisions		(15,822)	(16,746)	(4,485)
Charge-offs		(1,498)	(1,147)	(3,904)
Recoveries		2,027	2,825	996
Ending balance		69,896	85,189	100,257
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						3,370	8,610
ALLL for loans and leases collectively evaluated for impairment						66,526	76,579
Total allowance for loan and lease losses		85,189	100,257	80,229		69,896	85,189	100,257
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						95,107	82,803
Loans and leases collectively evaluated for impairment						8,179,441	7,470,145
Net Loans and Leases						8,274,548	7,552,948
Non-PCI Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		732	1,009	2,059
Reclassification	[1]			(815)
Provisions		1,569	(401)	(32)
Charge-offs		(178)	0	(312)
Recoveries		45	124	109
Ending balance		2,168	732	1,009
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						289	112
ALLL for loans and leases collectively evaluated for impairment						1,879	620
Total allowance for loan and lease losses		732	1,009	2,059		2,168	732	1,009
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						427	584
Loans and leases collectively evaluated for impairment						320,594	244,291
Net Loans and Leases						321,021	244,875
Non-PCI Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		30,727	22,362	14,050
Reclassification	[1]			7,551
Provisions		17,432	10,441	4,333
Charge-offs		(5,952)	(3,014)	(4,785)
Recoveries		909	938	1,213
Ending balance		43,116	30,727	22,362
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						1,118	1,743
ALLL for loans and leases collectively evaluated for impairment						41,998	28,984
Total allowance for loan and lease losses		30,727	22,362	14,050		43,116	30,727	22,362
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						17,910	11,040
Loans and leases collectively evaluated for impairment						2,351,048	1,977,594
Net Loans and Leases						2,368,958	1,988,634
Non-PCI Loans | Commercial | Lease financing
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		4,286	4,749	3,521
Reclassification	[1]			(253)
Provisions		1,602	(473)	1,646
Charge-offs		(402)	(100)	(272)
Recoveries		38	110	107
Ending balance		5,524	4,286	4,749
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						213	150
ALLL for loans and leases collectively evaluated for impairment						5,311	4,136
Total allowance for loan and lease losses		4,286	4,749	3,521		5,524	4,286	4,749
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						1,755	623
Loans and leases collectively evaluated for impairment						729,023	571,293
Net Loans and Leases						730,778	571,916
Non-PCI Loans | Commercial | Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		3,184	190	1,175
Reclassification	[1]			(1,288)
Provisions		(1,420)	3,007	308
Charge-offs		0	(13)	(6)
Recoveries		91	0	1
Ending balance		1,855	3,184	190
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						0	1,972
ALLL for loans and leases collectively evaluated for impairment						1,855	1,212
Total allowance for loan and lease losses		3,184	190	1,175		1,855	3,184	190
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						1,183	2,000
Loans and leases collectively evaluated for impairment						313,649	351,833
Net Loans and Leases						314,832	353,833
Non-PCI Loans | Noncommercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		892	681	1,721
Reclassification	[1]			(478)
Provisions		541	245	(379)
Charge-offs		(22)	(118)	(392)
Recoveries		74	84	209
Ending balance		1,485	892	681
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						49	71
ALLL for loans and leases collectively evaluated for impairment						1,436	821
Total allowance for loan and lease losses		892	681	1,721		1,485	892	681
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						784	1,340
Loans and leases collectively evaluated for impairment						219,289	203,676
Net Loans and Leases						220,073	205,016
Non-PCI Loans | Noncommercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		10,661	10,511	3,836
Reclassification	[1]			5,717
Provisions		4,202	1,219	2,786
Charge-offs		(1,619)	(1,260)	(2,387)
Recoveries		861	191	559
Ending balance		14,105	10,661	10,511
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						1,212	1,360
ALLL for loans and leases collectively evaluated for impairment						12,893	9,301
Total allowance for loan and lease losses		10,661	10,511	3,836		14,105	10,661	10,511
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						22,986	14,913
Loans and leases collectively evaluated for impairment						2,672,999	2,478,145
Net Loans and Leases						2,695,985	2,493,058
Non-PCI Loans | Noncommercial | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		18,650	16,239	25,185
Reclassification	[1]			(9,838)
Provisions		(927)	6,301	6,296
Charge-offs		(2,925)	(4,744)	(6,064)
Recoveries		1,173	854	660
Ending balance		15,971	18,650	16,239
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						299	1,052
ALLL for loans and leases collectively evaluated for impairment						15,672	17,598
Total allowance for loan and lease losses		18,650	16,239	25,185		15,971	18,650	16,239
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						5,883	3,675
Loans and leases collectively evaluated for impairment						2,517,223	2,558,125
Net Loans and Leases						2,523,106	2,561,800
Non-PCI Loans | Noncommercial | Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		16,555	13,541	25,389
Reclassification	[1]			(10,018)
Provisions		10,987	9,932	6,085
Charge-offs		(11,696)	(9,787)	(10,311)
Recoveries		3,650	2,869	2,396
Ending balance		19,496	16,555	13,541
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
ALLL for loans and leases individually evaluated for impairment						527	555
ALLL for loans and leases collectively evaluated for impairment						18,969	16,000
Total allowance for loan and lease losses		16,555	13,541	25,389		19,496	16,555	13,541
Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment						1,238	995
Loans and leases collectively evaluated for impairment						1,218,583	1,116,459
Net Loans and Leases						1,219,821	1,117,454
Non-PCI Loans | Noncommercial | Non-specific
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		0	0	15,850
Reclassification	[1]			(15,772)
Provisions		0	0	(78)
Charge-offs		0	0	0
Recoveries		0	0	0
Ending balance		0	0	0
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		0	0	15,850		0	0	0
PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		21,629	53,520	139,972
Reclassification	[1]			0
Provisions		(2,273)	(14,620)	(51,544)
Charge-offs		(3,044)	(17,271)	(34,908)
Recoveries		0	0	0
Net charge-offs		(3,044)	(17,271)	(34,908)
Ending balance		16,312	21,629	53,520
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		21,629	53,520	139,972		16,312	21,629	53,520
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans							1,186,498
PCI Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		150	1,320	31,186
Provisions		1,029	1,284	(22,942)
Charge-offs		(97)	(2,454)	(6,924)
Recoveries		0	0	0
Ending balance		1,082	150	1,320
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		150	1,320	31,186		1,082	150	1,320
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						33,880	78,079
PCI Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		10,135	29,906	50,275
Provisions		(1,426)	(7,903)	(3,872)
Charge-offs		(871)	(11,868)	(16,497)
Recoveries		0	0	0
Ending balance		7,838	10,135	29,906
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		10,135	29,906	50,275		7,838	10,135	29,906
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						525,468	577,518
PCI Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		75	1,354	11,234
Provisions		698	(1,385)	(8,949)
Charge-offs		0	(106)	(931)
Recoveries		0	0
Ending balance		773	75	1,354
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		75	1,354	11,234		773	75	1,354
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						17,076	40,193
PCI Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		1,240	5,275	8,897
Provisions		(470)	(2,023)	470
Charge-offs		(325)	(2,012)	(4,092)
Recoveries		0	0	0
Ending balance		445	1,240	5,275
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		1,240	5,275	8,897		445	1,240	5,275
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						15,182	27,254
PCI Loans | Noncommercial
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						356,902	460,375
PCI Loans | Noncommercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		183	682	8,287
Provisions		(183)	(395)	(4,170)
Charge-offs		0	(104)	(3,435)
Recoveries		0	0	0
Ending balance		0	183	682
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		183	682	8,287		0	183	682
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						0	912
PCI Loans | Noncommercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		5,820	11,802	19,837
Provisions		72	(5,576)	(5,487)
Charge-offs		(494)	(406)	(2,548)
Recoveries		0	0	0
Ending balance		5,398	5,820	11,802
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		5,820	11,802	19,837		5,398	5,820	11,802
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						302,158	382,340
PCI Loans | Noncommercial | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		3,999	2,959	9,754
Provisions		(2,720)	1,523	(6,399)
Charge-offs		(756)	(483)	(396)
Recoveries		0	0	0
Ending balance		523	3,999	2,959
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		3,999	2,959	9,754		523	3,999	2,959
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						52,471	74,109
PCI Loans | Noncommercial | Consumer
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						2,273	3,014
PCI Loans | Noncommercial | Consumer and Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		27	222	502
Provisions		727	(145)	(195)
Charge-offs		(501)	(50)	(85)
Recoveries		0	0	0
Ending balance		253	27	222
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses		$ 27	$ 222	$ 502		253	27	$ 222
Loan and Lease Acquired with Deteriorated Credit Quality [Abstract]
PCI Loans						$ 4,281	$ 6,093

[1] Reclassification results from enhancements to the ALLL calculation during the second quarter of 2013 that resulted in the allocation of $15.8 million previously designated as 'nonspecific' to other loan classes and the absorption of $7.4 million of the reserve for unfunded commitments related to unfunded, revocable loan commitments into the ALLL. Further discussion is contained in Note A.