Loans and Leases (Impaired Loans) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013		Dec. 31, 2012
Financing Receivable Impaired [Line Items]
Loans written down to fair value of collateral	$ 19,666		$ 28,658
Total impaired loans without a related reserve	166,348		201,186
Direct charge-offs	18,873		31,482
Subsequently Impaired Loans	9,249		6,625
Purchased Impaired Loans	141,486		162,251
Impaired Loans Without A Related Reserve [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	185,221		232,668
Recorded Investment in Impaired Loans	166,348	[1]	201,186	[2]
Related Charge-offs	18,873		31,482
Average Recorded Investment in Impaired Loans	161,859	[3]	202,781	[3]
Interest Income Recognized	2,238		3,243
Impaired Loans Without A Related Reserve [Member] | Originated Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	51,928		76,120
Recorded Investment in Impaired Loans	34,111		45,560
Related Charge-offs	17,817		30,560
Average Recorded Investment in Impaired Loans	34,927	[3]	49,975	[3]
Interest Income Recognized	210		764
Impaired Loans Without A Related Reserve [Member] | Purchased Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	133,293		156,548
Recorded Investment in Impaired Loans	132,237		155,626
Related Charge-offs	1,056		922
Average Recorded Investment in Impaired Loans	126,932	[3]	152,806	[3]
Interest Income Recognized	2,028		2,479
Impaired Loans Without A Related Reserve [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	19,583		23,959
Recorded Investment in Impaired Loans	19,550		23,877
Related Charge-offs	33		82
Average Recorded Investment in Impaired Loans	18,184	[3]	24,603	[3]
Interest Income Recognized	215		233
Impaired Loans Without A Related Reserve [Member] | Real Estate - Construction [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	29,405		48,394
Recorded Investment in Impaired Loans	20,177		32,717
Related Charge-offs	9,228		15,677
Average Recorded Investment in Impaired Loans	18,968	[3]	34,223	[3]
Interest Income Recognized	75		882
Impaired Loans Without A Related Reserve [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	40,999		26,298
Recorded Investment in Impaired Loans	39,279		25,261
Related Charge-offs	1,720		1,037
Average Recorded Investment in Impaired Loans	25,199	[3]	25,417	[3]
Interest Income Recognized	329		398
Impaired Loans Without A Related Reserve [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	95,120		133,903
Recorded Investment in Impaired Loans	87,228		119,217
Related Charge-offs	7,892		14,686
Average Recorded Investment in Impaired Loans	99,398	[3]	118,424	[3]
Interest Income Recognized	1,617		1,727
Impaired Loans Without A Related Reserve [Member] | Consumer [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	114		114
Recorded Investment in Impaired Loans	114		114
Related Charge-offs	0		0
Average Recorded Investment in Impaired Loans	110	[3]	114	[3]
Interest Income Recognized	2		3
Impaired Loans With A Related Reserve [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	120,802		99,096
Recorded Investment in Impaired Loans	93,166		81,467
Related Charge-offs	27,636		17,629
Related Allowance	13,081		15,736
Average Recorded Investment in Impaired Loans	91,478	[3]	83,437	[3]
Interest Income Recognized	1,163		1,103
Impaired Loans With A Related Reserve [Member] | Originated Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	111,426		92,471
Recorded Investment in Impaired Loans	83,917		74,842
Related Charge-offs	27,509		17,629
Related Allowance	11,145		14,649
Average Recorded Investment in Impaired Loans	82,026	[3]	76,823	[3]
Interest Income Recognized	1,007		1,033
Impaired Loans With A Related Reserve [Member] | Purchased Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	9,376		6,625
Recorded Investment in Impaired Loans	9,249		6,625
Related Charge-offs	127		0
Related Allowance	1,936		1,087
Average Recorded Investment in Impaired Loans	9,452	[3]	6,614	[3]
Interest Income Recognized	156		70
Impaired Loans With A Related Reserve [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	8,452		4,240
Recorded Investment in Impaired Loans	8,327		4,184
Related Charge-offs	125		56
Related Allowance	2,240		3,267
Average Recorded Investment in Impaired Loans	8,500	[3]	4,278	[3]
Interest Income Recognized	122		47
Impaired Loans With A Related Reserve [Member] | Real Estate - Construction [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	12,735		12,894
Recorded Investment in Impaired Loans	4,126		5,577
Related Charge-offs	8,609		7,317
Related Allowance	1,060		952
Average Recorded Investment in Impaired Loans	4,115	[3]	5,883	[3]
Interest Income Recognized	5		237
Impaired Loans With A Related Reserve [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	32,561		32,640
Recorded Investment in Impaired Loans	31,659		32,375
Related Charge-offs	902		265
Related Allowance	3,655		6,633
Average Recorded Investment in Impaired Loans	31,742	[3]	32,498	[3]
Interest Income Recognized	408		333
Impaired Loans With A Related Reserve [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	65,716		49,322
Recorded Investment in Impaired Loans	47,716		39,331
Related Charge-offs	18,000		9,991
Related Allowance	5,981		4,884
Average Recorded Investment in Impaired Loans	45,750	[3]	40,778	[3]
Interest Income Recognized	592		486
Impaired Loans With A Related Reserve [Member] | Consumer [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	1,338		0
Recorded Investment in Impaired Loans	1,338		0
Related Charge-offs	0		0
Related Allowance	145		0
Average Recorded Investment in Impaired Loans	1,371	[3]	0	[3]
Interest Income Recognized	36		0
Impaired Loans [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	306,023		331,764
Recorded Investment in Impaired Loans	259,514		282,653
Related Charge-offs	46,509		49,111
Related Allowance	13,081		15,736
Average Recorded Investment in Impaired Loans	253,337	[3]	286,218	[3]
Interest Income Recognized	3,401		4,346
Impaired Loans [Member] | Originated Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	163,354		168,591
Recorded Investment in Impaired Loans	118,028		120,402
Related Charge-offs	45,326		48,189
Related Allowance	11,145		14,649
Average Recorded Investment in Impaired Loans	116,953	[3]	126,798	[3]
Interest Income Recognized	1,217		1,797
Impaired Loans [Member] | Purchased Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	142,669	[4]	163,173	[5]
Recorded Investment in Impaired Loans	141,486	[4]	162,251	[5]
Related Charge-offs	1,183	[4]	922	[5]
Related Allowance	1,936	[4]	1,087	[5]
Average Recorded Investment in Impaired Loans	136,384	[3],[4]	159,420	[3],[5]
Interest Income Recognized	2,184	[4]	2,549	[5]
Impaired Loans [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	28,035		28,199
Recorded Investment in Impaired Loans	27,877		28,061
Related Charge-offs	158		138
Related Allowance	2,240		3,267
Average Recorded Investment in Impaired Loans	26,684	[3]	28,881	[3]
Interest Income Recognized	337		280
Impaired Loans [Member] | Real Estate - Construction [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	42,140		61,288
Recorded Investment in Impaired Loans	24,303		38,294
Related Charge-offs	17,837		22,994
Related Allowance	1,060		952
Average Recorded Investment in Impaired Loans	23,083	[3]	40,106	[3]
Interest Income Recognized	80		1,119
Impaired Loans [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	73,560		58,938
Recorded Investment in Impaired Loans	70,938		57,636
Related Charge-offs	2,622		1,302
Related Allowance	3,655		6,633
Average Recorded Investment in Impaired Loans	56,941	[3]	57,915	[3]
Interest Income Recognized	737		731
Impaired Loans [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	160,836		183,225
Recorded Investment in Impaired Loans	134,944		158,548
Related Charge-offs	25,892		24,677
Related Allowance	5,981		4,884
Average Recorded Investment in Impaired Loans	145,148	[3]	159,202	[3]
Interest Income Recognized	2,209		2,213
Impaired Loans [Member] | Consumer [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	1,452		114
Recorded Investment in Impaired Loans	1,452		114
Related Charge-offs	0		0
Related Allowance	145		0
Average Recorded Investment in Impaired Loans	1,481	[3]	114	[3]
Interest Income Recognized	$ 38		$ 3

[1] $19,666 of the $166,348 total impaired loans without a related reserve represents loans that had been written down to the fair value of the underlying collateral adjusted for selling costs through direct charge-offs of $18,873.

[2] $28,658 of the $201,186 total impaired loans without a related reserve represents loans that had been written down to the fair value of the underlying collateral adjusted for selling costs through direct charge-offs of $31,482.

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

[4] $9,249 of the $141,486 purchased impaired loans were subsequently impaired after being acquired.

[5] $6,625 of the $162,251 purchased impaired loans were subsequently impaired after being acquired.