Loans and Leases (Impaired Loans) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2012		Dec. 31, 2011
Financing Receivable, Impaired [Line Items]
Loans written down to fair value of collateral	$ 21,912		$ 48,234
Total impaired loans without a related reserve	197,684		85,619
Direct charge-offs	23,979		63,683
Impaired loans with related reserve	168,018
Loans impaired after acquired	6,408
Impaired Loans Without A Related Reserve [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	221,663		149,302
Recorded Investment in Impaired Loans	197,684	[1]	85,619	[2]
Related Charge-offs	23,979		63,683
Average Recorded Investment in a Impaired a Loans	209,693	[3]	98,745	[3]
Interest Income Recognized	3,123		3,323
Impaired Loans Without A Related Reserve [Member] | Legacy Loans And Leases [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	60,053		109,075
Recorded Investment in Impaired Loans	36,074		45,442
Related Charge-offs	23,979		63,633
Average Recorded Investment in a Impaired a Loans	50,704	[3]	88,262	[3]
Interest Income Recognized	395		2,713
Impaired Loans Without A Related Reserve [Member] | Purchased Loans And Leases [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	161,610		40,227
Recorded Investment in Impaired Loans	161,610		40,177
Related Charge-offs	0		50
Average Recorded Investment in a Impaired a Loans	158,989	[3]	10,483	[3]
Interest Income Recognized	2,728		610
Impaired Loans Without A Related Reserve [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	26,184		6,621
Recorded Investment in Impaired Loans	25,299		6,621
Related Charge-offs	885		0
Average Recorded Investment in a Impaired a Loans	24,678	[3]	11,159	[3]
Interest Income Recognized	294		291
Impaired Loans Without A Related Reserve [Member] | Real Estate - Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	40,510		52,801
Recorded Investment in Impaired Loans	34,025		25,968
Related Charge-offs	6,485		26,833
Average Recorded Investment in a Impaired a Loans	35,075	[3]	29,464	[3]
Interest Income Recognized	461		761
Impaired Loans Without A Related Reserve [Member] | Real Estate Secured - Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	26,649		20,411
Recorded Investment in Impaired Loans	26,288		17,540
Related Charge-offs	361		2,871
Average Recorded Investment in a Impaired a Loans	21,639	[3]	16,473	[3]
Interest Income Recognized	394		788
Impaired Loans Without A Related Reserve [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	128,203		69,469
Recorded Investment in Impaired Loans	111,955		35,490
Related Charge-offs	16,248		33,979
Average Recorded Investment in a Impaired a Loans	128,181	[3]	41,612	[3]
Interest Income Recognized	1,971		1,479
Impaired Loans Without A Related Reserve [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	117		0
Recorded Investment in Impaired Loans	117		0
Related Charge-offs	0		0
Average Recorded Investment in a Impaired a Loans	120	[3]	37	[3]
Interest Income Recognized	3		4
Impaired Loans With A Related Reserve [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	113,296		118,934
Recorded Investment in Impaired Loans	87,380		92,058
Related Charge-offs	25,916		26,876
Related Allowance	17,624		20,996
Average Recorded Investment in a Impaired a Loans	88,497	[3]	106,264	[3]
Interest Income Recognized	653		3,336
Impaired Loans With A Related Reserve [Member] | Legacy Loans And Leases [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	106,888		118,934
Recorded Investment in Impaired Loans	80,972		92,058
Related Charge-offs	25,916		26,876
Related Allowance	15,877		20,996
Average Recorded Investment in a Impaired a Loans	82,067	[3]	106,264	[3]
Interest Income Recognized	542		3,336
Impaired Loans With A Related Reserve [Member] | Purchased Loans And Leases [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	6,408		0
Recorded Investment in Impaired Loans	6,408		0
Related Charge-offs	0		0
Related Allowance	1,747		0
Average Recorded Investment in a Impaired a Loans	6,430	[3]	0	[3]
Interest Income Recognized	111		0
Impaired Loans With A Related Reserve [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	7,380		6,870
Recorded Investment in Impaired Loans	5,672		6,870
Related Charge-offs	1,708		0
Related Allowance	907		3,421
Average Recorded Investment in a Impaired a Loans	5,779	[3]	9,085	[3]
Interest Income Recognized	25		239
Impaired Loans With A Related Reserve [Member] | Real Estate - Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	28,922		21,613
Recorded Investment in Impaired Loans	14,865		15,015
Related Charge-offs	14,057		6,598
Related Allowance	1,837		2,243
Average Recorded Investment in a Impaired a Loans	15,581	[3]	22,022	[3]
Interest Income Recognized	0		307
Impaired Loans With A Related Reserve [Member] | Real Estate Secured - Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	23,181		17,311
Recorded Investment in Impaired Loans	22,506		16,227
Related Charge-offs	675		1,084
Related Allowance	5,837		2,807
Average Recorded Investment in a Impaired a Loans	22,524	[3]	15,733	[3]
Interest Income Recognized	253		558
Impaired Loans With A Related Reserve [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	53,507		72,482
Recorded Investment in Impaired Loans	44,031		53,288
Related Charge-offs	9,476		19,194
Related Allowance	8,926		11,871
Average Recorded Investment in a Impaired a Loans	44,155	[3]	59,222	[3]
Interest Income Recognized	369		2,224
Impaired Loans With A Related Reserve [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	306		658
Recorded Investment in Impaired Loans	306		658
Related Charge-offs	0		0
Related Allowance	117		654
Average Recorded Investment in a Impaired a Loans	458	[3]	202	[3]
Interest Income Recognized	6		8
Impaired Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	334,959		268,236
Recorded Investment in Impaired Loans	285,064		177,677
Related Charge-offs	49,895		90,559
Related Allowance	17,624		20,996
Average Recorded Investment in a Impaired a Loans	298,190	[3]	205,009	[3]
Interest Income Recognized	3,776		6,659
Impaired Loans [Member] | Legacy Loans And Leases [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	166,941		228,009
Recorded Investment in Impaired Loans	117,046		137,500
Related Charge-offs	49,895		90,559
Related Allowance	15,877		20,996
Average Recorded Investment in a Impaired a Loans	132,771	[3]	194,526	[3]
Interest Income Recognized	937		6,049
Impaired Loans [Member] | Purchased Loans And Leases [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	168,018	[4]	40,227
Recorded Investment in Impaired Loans	168,018	[4]	40,177
Related Charge-offs	0	[4]	0
Related Allowance	1,747	[4]	0
Average Recorded Investment in a Impaired a Loans	165,419	[3],[4]	10,483	[3]
Interest Income Recognized	2,839	[4]	610
Impaired Loans [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	33,564		13,491
Recorded Investment in Impaired Loans	30,971		13,491
Related Charge-offs	2,593		0
Related Allowance	907		3,421
Average Recorded Investment in a Impaired a Loans	30,457	[3]	20,244	[3]
Interest Income Recognized	319		530
Impaired Loans [Member] | Real Estate - Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	69,432		74,414
Recorded Investment in Impaired Loans	48,890		40,983
Related Charge-offs	20,542		33,431
Related Allowance	1,837		2,243
Average Recorded Investment in a Impaired a Loans	50,656	[3]	51,486	[3]
Interest Income Recognized	461		1,068
Impaired Loans [Member] | Real Estate Secured - Residential [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	49,830		37,722
Recorded Investment in Impaired Loans	48,794		33,767
Related Charge-offs	1,036		3,955
Related Allowance	5,837		2,807
Average Recorded Investment in a Impaired a Loans	44,163	[3]	32,206	[3]
Interest Income Recognized	647		1,346
Impaired Loans [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	181,709		141,951
Recorded Investment in Impaired Loans	155,985		88,778
Related Charge-offs	25,724		53,173
Related Allowance	8,926		11,871
Average Recorded Investment in a Impaired a Loans	172,336	[3]	100,834	[3]
Interest Income Recognized	2,340		3,703
Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	423		658
Recorded Investment in Impaired Loans	423		658
Related Charge-offs	0		0
Related Allowance	117		654
Average Recorded Investment in a Impaired a Loans	578	[3]	239	[3]
Interest Income Recognized	$ 9		$ 12

[1] $21,912 of the $197,684 total impaired loans without a related reserve represents loans that had been written down to the fair value of the underlying collateral through direct charge-offs of $23,979.

[2] $48,234 of the $85,619 total impaired loans without a related reserve represents loans that had been written down to the fair value of the underlying collateral through direct charge-offs of $63,683.

[3] Average recorded investment in impaired loans is calculated on a quarterly basis using daily balances.

[4] $6,408 of the $168,018 purchased impaired loans were subsequently impaired after being acquired.