Allowance for Loan and Lease Losses (Summary of Activity In Allowance for Loan and Lease Losses) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Loans and Leases, Baseline for Meaurement						$ 500,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Net loans and leases					$ 19,311,868,000	18,564,999,000
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					1,123,239,000	1,186,498,000	$ 1,109,933,000	$ 1,029,426,000
Allowance for loan and lease losses					208,317,000	204,466,000
Commercial
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					697,045,000	726,123,000
Commercial | Construction and land development
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					48,208,000	78,079,000
Commercial | Mortgage
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					611,505,000	577,518,000
Commercial | Other commercial real estate
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					14,353,000	40,193,000
Commercial | Commercial and industrial
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					20,382,000	27,254,000
Commercial | Other
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					2,597,000	3,079,000
Noncommerical
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					426,194,000	460,375,000
Noncommerical | Construction and land development
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					345,000	912,000
Noncommerical | Mortgage
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					358,307,000	382,340,000
Noncommerical | Revolving mortgage
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					64,340,000	74,109,000
Noncommerical | Consumer
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					3,202,000	3,014,000
Non-PCI Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Related Allowance					12,592,000	15,717,000
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 187,934,000	$ 177,949,000	$ 182,837,000	$ 179,874,000
Provision for Loan, Lease, and Other Losses	8,994,000	2,230,000	17,650,000	2,600,000
Charge-offs	(6,050,000)	(4,771,000)	(12,080,000)	(9,193,000)
Recoveries	1,971,000	1,507,000	4,442,000	3,634,000
Ending balance	192,849,000	176,915,000	192,849,000	176,915,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					125,006,000	119,593,000
Loans and leases collectively evaluated for impairment					18,271,940,000	17,463,374,000
Net loans and leases					18,396,946,000	17,582,967,000
ALLL for loans and leases individually evaluated for impairment					12,592,000	15,717,000
ALLL for loans and leases collectively evaluated for impairment					180,257,000	167,120,000
Total allowance for loan and lease losses	187,934,000	177,949,000	182,837,000	179,874,000	192,849,000	182,837,000	176,915,000	179,874,000
Non-PCI Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	13,108,000	12,246,000	11,961,000	10,335,000
Provision for Loan, Lease, and Other Losses	88,000	(1,135,000)	1,191,000	750,000
Charge-offs	(221,000)	0	(239,000)	0
Recoveries	104,000	5,000	166,000	31,000
Ending balance	13,079,000	11,116,000	13,079,000	11,116,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					3,092,000	1,620,000
Loans and leases collectively evaluated for impairment					544,059,000	491,513,000
Net loans and leases					547,151,000	493,133,000
ALLL for loans and leases individually evaluated for impairment					445,000	92,000
ALLL for loans and leases collectively evaluated for impairment					12,634,000	11,869,000
Total allowance for loan and lease losses	13,108,000	12,246,000	11,961,000	10,335,000	13,079,000	11,961,000	11,116,000	10,335,000
Non-PCI Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	82,038,000	94,217,000	85,189,000	100,257,000
Provision for Loan, Lease, and Other Losses	(1,878,000)	(1,961,000)	(5,557,000)	(8,940,000)
Charge-offs	(47,000)	(272,000)	(280,000)	(440,000)
Recoveries	323,000	145,000	1,084,000	1,252,000
Ending balance	80,436,000	92,129,000	80,436,000	92,129,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					83,555,000	82,803,000
Loans and leases collectively evaluated for impairment					7,778,035,000	7,470,145,000
Net loans and leases					7,861,590,000	7,552,948,000
ALLL for loans and leases individually evaluated for impairment					7,744,000	8,610,000
ALLL for loans and leases collectively evaluated for impairment					72,692,000	76,579,000
Total allowance for loan and lease losses	82,038,000	94,217,000	85,189,000	100,257,000	80,436,000	85,189,000	92,129,000	100,257,000
Non-PCI Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,031,000	945,000	732,000	1,009,000
Provision for Loan, Lease, and Other Losses	(227,000)	(155,000)	231,000	(229,000)
Charge-offs	(9,000)	0	(178,000)	0
Recoveries	9,000	16,000	19,000	26,000
Ending balance	804,000	806,000	804,000	806,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					401,000	584,000
Loans and leases collectively evaluated for impairment					287,813,000	244,291,000
Net loans and leases					288,214,000	244,875,000
ALLL for loans and leases individually evaluated for impairment					101,000	112,000
ALLL for loans and leases collectively evaluated for impairment					703,000	620,000
Total allowance for loan and lease losses	1,031,000	945,000	732,000	1,009,000	804,000	732,000	806,000	1,009,000
Non-PCI Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	36,954,000	24,021,000	30,727,000	22,362,000
Provision for Loan, Lease, and Other Losses	4,547,000	3,033,000	12,093,000	5,009,000
Charge-offs	(2,318,000)	(531,000)	(4,031,000)	(1,027,000)
Recoveries	209,000	386,000	603,000	565,000
Ending balance	39,392,000	26,909,000	39,392,000	26,909,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					12,416,000	11,040,000
Loans and leases collectively evaluated for impairment					2,187,175,000	1,977,894,000
Net loans and leases					2,199,591,000	1,988,934,000
ALLL for loans and leases individually evaluated for impairment					1,771,000	1,743,000
ALLL for loans and leases collectively evaluated for impairment					37,621,000	28,984,000
Total allowance for loan and lease losses	36,954,000	24,021,000	30,727,000	22,362,000	39,392,000	30,727,000	26,909,000	22,362,000
Non-PCI Loans | Commercial | Lease financing
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,293,000	4,183,000	4,286,000	4,749,000
Provision for Loan, Lease, and Other Losses	408,000	176,000	419,000	(348,000)
Charge-offs	(6,000)	(14,000)	(21,000)	(72,000)
Recoveries	11,000	20,000	22,000	36,000
Ending balance	4,706,000	4,365,000	4,706,000	4,365,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					1,448,000	623,000
Loans and leases collectively evaluated for impairment					642,060,000	571,293,000
Net loans and leases					643,508,000	571,916,000
ALLL for loans and leases individually evaluated for impairment					146,000	150,000
ALLL for loans and leases collectively evaluated for impairment					4,560,000	4,136,000
Total allowance for loan and lease losses	4,293,000	4,183,000	4,286,000	4,749,000	4,706,000	4,286,000	4,365,000	4,749,000
Non-PCI Loans | Commercial | Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,981,000	454,000	3,184,000	190,000
Provision for Loan, Lease, and Other Losses	(1,824,000)	163,000	(2,042,000)	435,000
Charge-offs	0	(5,000)	0	(13,000)
Recoveries	31,000	0	46,000	0
Ending balance	1,188,000	612,000	1,188,000	612,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					1,732,000	2,000,000
Loans and leases collectively evaluated for impairment					336,657,000	351,833,000
Net loans and leases					338,389,000	353,833,000
ALLL for loans and leases individually evaluated for impairment					17,000	1,972,000
ALLL for loans and leases collectively evaluated for impairment					1,171,000	1,212,000
Total allowance for loan and lease losses	2,981,000	454,000	3,184,000	190,000	1,188,000	3,184,000	612,000	190,000
Non-PCI Loans | Noncommerical | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,056,000	1,249,000	892,000	681,000
Provision for Loan, Lease, and Other Losses	74,000	(323,000)	192,000	254,000
Charge-offs	0	(23,000)	(22,000)	(94,000)
Recoveries	3,000	2,000	71,000	64,000
Ending balance	1,133,000	905,000	1,133,000	905,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					860,000	1,340,000
Loans and leases collectively evaluated for impairment					226,420,000	203,676,000
Net loans and leases					227,280,000	205,016,000
ALLL for loans and leases individually evaluated for impairment					0	71,000
ALLL for loans and leases collectively evaluated for impairment					1,133,000	821,000
Total allowance for loan and lease losses	1,056,000	1,249,000	892,000	681,000	1,133,000	892,000	905,000	681,000
Non-PCI Loans | Noncommerical | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,328,000	10,944,000	10,661,000	10,511,000
Provision for Loan, Lease, and Other Losses	1,162,000	(1,557,000)	1,975,000	(948,000)
Charge-offs	(90,000)	(234,000)	(374,000)	(418,000)
Recoveries	305,000	148,000	443,000	156,000
Ending balance	12,705,000	9,301,000	12,705,000	9,301,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					16,424,000	14,913,000
Loans and leases collectively evaluated for impairment					2,580,640,000	2,478,145,000
Net loans and leases					2,597,064,000	2,493,058,000
ALLL for loans and leases individually evaluated for impairment					1,623,000	1,360,000
ALLL for loans and leases collectively evaluated for impairment					11,082,000	9,301,000
Total allowance for loan and lease losses	11,328,000	10,944,000	10,661,000	10,511,000	12,705,000	10,661,000	9,301,000	10,511,000
Non-PCI Loans | Noncommerical | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	17,529,000	16,408,000	18,650,000	16,239,000
Provision for Loan, Lease, and Other Losses	31,000	1,252,000	(431,000)	2,605,000
Charge-offs	(616,000)	(1,064,000)	(1,409,000)	(2,324,000)
Recoveries	346,000	201,000	480,000	277,000
Ending balance	17,290,000	16,797,000	17,290,000	16,797,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					3,961,000	3,675,000
Loans and leases collectively evaluated for impairment					2,525,975,000	2,558,125,000
Net loans and leases					2,529,936,000	2,561,800,000
ALLL for loans and leases individually evaluated for impairment					168,000	1,052,000
ALLL for loans and leases collectively evaluated for impairment					17,122,000	17,598,000
Total allowance for loan and lease losses	17,529,000	16,408,000	18,650,000	16,239,000	17,290,000	18,650,000	16,797,000	16,239,000
Non-PCI Loans | Noncommerical | Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	17,616,000	13,282,000	16,555,000	13,541,000
Provision for Loan, Lease, and Other Losses	6,613,000	2,737,000	9,579,000	4,012,000
Charge-offs	(2,743,000)	(2,628,000)	(5,526,000)	(4,805,000)
Recoveries	630,000	584,000	1,508,000	1,227,000
Ending balance	22,116,000	13,975,000	22,116,000	13,975,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment					1,117,000	995,000
Loans and leases collectively evaluated for impairment					1,163,106,000	1,116,459,000
Net loans and leases					1,164,223,000	1,117,454,000
ALLL for loans and leases individually evaluated for impairment					577,000	555,000
ALLL for loans and leases collectively evaluated for impairment					21,539,000	16,000,000
Total allowance for loan and lease losses	17,616,000	13,282,000	16,555,000	13,541,000	22,116,000	16,555,000	13,975,000	13,541,000
PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	17,619,000	44,993,000	21,629,000	53,520,000
Provision for Loan, Lease, and Other Losses	(1,275,000)	(9,529,000)	(4,139,000)	(11,802,000)
Charge-offs	(876,000)	(6,133,000)	(2,022,000)	(12,387,000)
Recoveries	0	0	0	0
Ending balance	15,468,000	29,331,000	15,468,000	29,331,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	17,619,000	44,993,000	21,629,000	53,520,000	15,468,000	21,629,000	29,331,000	53,520,000
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					1,123,239,000	1,186,498,000
PCI Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	341,000	4,476,000	150,000	1,320,000
Provision for Loan, Lease, and Other Losses	325,000	(77,000)	516,000	3,278,000
Charge-offs	(97,000)	(596,000)	(97,000)	(795,000)
Recoveries	0	0	0	0
Ending balance	569,000	3,803,000	569,000	3,803,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	341,000	4,476,000	150,000	1,320,000	569,000	150,000	3,803,000	1,320,000
PCI Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,876,000	23,003,000	10,135,000	29,906,000
Provision for Loan, Lease, and Other Losses	(2,065,000)	(1,185,000)	(2,990,000)	(4,571,000)
Charge-offs	(383,000)	(4,503,000)	(717,000)	(8,020,000)
Recoveries	0	0	0	0
Ending balance	6,428,000	17,315,000	6,428,000	17,315,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	8,876,000	23,003,000	10,135,000	29,906,000	6,428,000	10,135,000	17,315,000	29,906,000
PCI Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	194,000	1,204,000	75,000	1,354,000
Provision for Loan, Lease, and Other Losses	(125,000)	(797,000)	(6,000)	(947,000)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	69,000	407,000	69,000	407,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	194,000	1,204,000	75,000	1,354,000	69,000	75,000	407,000	1,354,000
PCI Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,000	2,256,000	1,240,000	5,275,000
Provision for Loan, Lease, and Other Losses	399,000	(1,729,000)	(632,000)	(2,065,000)
Charge-offs	(87,000)	(152,000)	(285,000)	(2,835,000)
Recoveries	0	0	0	0
Ending balance	323,000	375,000	323,000	375,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	11,000	2,256,000	1,240,000	5,275,000	323,000	1,240,000	375,000	5,275,000
PCI Loans | Noncommerical | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	31,000	583,000	183,000	682,000
Provision for Loan, Lease, and Other Losses	(31,000)	(583,000)	(183,000)	(682,000)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	0	0	0	0
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	31,000	583,000	183,000	682,000	0	183,000	0	682,000
PCI Loans | Noncommerical | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,872,000	9,764,000	5,820,000	11,802,000
Provision for Loan, Lease, and Other Losses	1,165,000	(2,176,000)	302,000	(4,476,000)
Charge-offs	(195,000)	(495,000)	(280,000)	(233,000)
Recoveries	0	0	0	0
Ending balance	5,842,000	7,093,000	5,842,000	7,093,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	4,872,000	9,764,000	5,820,000	11,802,000	5,842,000	5,820,000	7,093,000	11,802,000
PCI Loans | Noncommerical | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,271,000	3,493,000	3,999,000	2,959,000
Provision for Loan, Lease, and Other Losses	(1,112,000)	(3,031,000)	(1,767,000)	(2,397,000)
Charge-offs	(108,000)	(381,000)	(181,000)	(481,000)
Recoveries	0	0	0	0
Ending balance	2,051,000	81,000	2,051,000	81,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	3,271,000	3,493,000	3,999,000	2,959,000	2,051,000	3,999,000	81,000	2,959,000
PCI Loans | Noncommerical | Consumer and Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	23,000	214,000	27,000	222,000
Provision for Loan, Lease, and Other Losses	169,000	49,000	621,000	58,000
Charge-offs	(6,000)	(6,000)	(462,000)	(23,000)
Recoveries	0	0	0	0
Ending balance	186,000	257,000	186,000	257,000
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	$ 23,000	$ 214,000	$ 27,000	$ 222,000	186,000	27,000	$ 257,000	$ 222,000
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality					$ 5,799,000	$ 6,093,000