Loans and Leases (Impaired Loans) (Detail) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Financing Receivable Impaired [Line Items]
Loans written down to fair value of collateral	$ 34,632,000		$ 43,363,000
Total impaired loans without a related reserve	148,312,000		195,033,000
Direct charge-offs	26,512,000		25,986,000
Subsequently Impaired Loans	5,163,000		9,498,000
Purchased Impaired Loans	106,835,000		138,445,000
Impaired Loans Without A Related Reserve [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	174,824,000		221,019,000
Recorded Investment in Impaired Loans	148,312,000	[1]	195,033,000	[2]
Related Charge-offs	26,512,000		25,986,000
Average Recorded Investment in Impaired Loans	127,102,000	[3]	196,848,000	[3]
Interest Income Recognized	1,830,000		2,903,000
Impaired Loans Without A Related Reserve [Member] | Originated Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	70,279,000		88,900,000
Recorded Investment in Impaired Loans	46,640,000		66,086,000
Related Charge-offs	23,639,000		22,814,000
Average Recorded Investment in Impaired Loans	26,627,000	[3]	65,341,000	[3]
Interest Income Recognized	455,000		749,000
Impaired Loans Without A Related Reserve [Member] | Purchased Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	104,545,000		132,119,000
Recorded Investment in Impaired Loans	101,672,000		128,947,000
Related Charge-offs	2,873,000		3,172,000
Average Recorded Investment in Impaired Loans	100,475,000	[3]	131,507,000	[3]
Interest Income Recognized	1,375,000		2,154,000
Impaired Loans Without A Related Reserve [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	16,536,000		31,196,000
Recorded Investment in Impaired Loans	13,622,000		28,034,000
Related Charge-offs	2,914,000		3,162,000
Average Recorded Investment in Impaired Loans	13,666,000	[3]	29,316,000	[3]
Interest Income Recognized	152,000		390,000
Impaired Loans Without A Related Reserve [Member] | Real Estate - Construction [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	8,113,000		17,851,000
Recorded Investment in Impaired Loans	7,514,000		14,215,000
Related Charge-offs	599,000		3,636,000
Average Recorded Investment in Impaired Loans	8,220,000	[3]	14,715,000	[3]
Interest Income Recognized	73,000		140,000
Impaired Loans Without A Related Reserve [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	21,582,000		28,308,000
Recorded Investment in Impaired Loans	21,408,000		27,645,000
Related Charge-offs	174,000		663,000
Average Recorded Investment in Impaired Loans	17,743,000	[3]	27,800,000	[3]
Interest Income Recognized	232,000		297,000
Impaired Loans Without A Related Reserve [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	128,593,000		143,664,000
Recorded Investment in Impaired Loans	105,768,000		125,139,000
Related Charge-offs	22,825,000		18,525,000
Average Recorded Investment in Impaired Loans	87,473,000	[3]	125,003,000	[3]
Interest Income Recognized	1,373,000		2,076,000
Impaired Loans Without A Related Reserve [Member] | Consumer [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	0		0
Recorded Investment in Impaired Loans	0		0
Related Charge-offs	0		0
Average Recorded Investment in Impaired Loans	0	[3]	14,000	[3]
Interest Income Recognized	0		0
Impaired Loans With A Related Reserve [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	77,157,000		88,795,000
Recorded Investment in Impaired Loans	59,835,000		67,841,000
Related Charge-offs	17,322,000		20,954,000
Related Specific Allowance	12,394,000		13,625,000
Average Recorded Investment in Impaired Loans	48,382,000	[3]	65,585,000	[3]
Interest Income Recognized	1,022,000		1,317,000
Impaired Loans With A Related Reserve [Member] | Originated Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	71,261,000		78,015,000
Recorded Investment in Impaired Loans	54,672,000		58,343,000
Related Charge-offs	16,589,000		19,672,000
Related Specific Allowance	10,780,000		11,612,000
Average Recorded Investment in Impaired Loans	45,605,000	[3]	55,881,000	[3]
Interest Income Recognized	969,000		1,172,000
Impaired Loans With A Related Reserve [Member] | Purchased Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	5,896,000		10,780,000
Recorded Investment in Impaired Loans	5,163,000		9,498,000
Related Charge-offs	733,000		1,282,000
Related Specific Allowance	1,614,000		2,013,000
Average Recorded Investment in Impaired Loans	2,777,000	[3]	9,704,000	[3]
Interest Income Recognized	53,000		145,000
Impaired Loans With A Related Reserve [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	13,156,000		6,864,000
Recorded Investment in Impaired Loans	13,156,000		5,879,000
Related Charge-offs	0		985,000
Related Specific Allowance	6,116,000		3,008,000
Average Recorded Investment in Impaired Loans	13,073,000	[3]	5,893,000	[3]
Interest Income Recognized	162,000		154,000
Impaired Loans With A Related Reserve [Member] | Real Estate - Construction [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	8,173,000		15,202,000
Recorded Investment in Impaired Loans	3,136,000		7,288,000
Related Charge-offs	5,037,000		7,914,000
Related Specific Allowance	655,000		1,819,000
Average Recorded Investment in Impaired Loans	3,330,000	[3]	5,831,000	[3]
Interest Income Recognized	55,000		228,000
Impaired Loans With A Related Reserve [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	23,818,000		37,499,000
Recorded Investment in Impaired Loans	22,397,000		35,153,000
Related Charge-offs	1,421,000		2,346,000
Related Specific Allowance	3,209,000		4,753,000
Average Recorded Investment in Impaired Loans	5,355,000	[3]	35,273,000	[3]
Interest Income Recognized	280,000		554,000
Impaired Loans With A Related Reserve [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	30,931,000		27,238,000
Recorded Investment in Impaired Loans	20,095,000		17,529,000
Related Charge-offs	10,836,000		9,709,000
Related Specific Allowance	2,300,000		3,827,000
Average Recorded Investment in Impaired Loans	26,591,000	[3]	16,546,000	[3]
Interest Income Recognized	497,000		325,000
Impaired Loans With A Related Reserve [Member] | Consumer [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	1,079,000		1,992,000
Recorded Investment in Impaired Loans	1,051,000		1,992,000
Related Charge-offs	28,000		0
Related Specific Allowance	114,000		218,000
Average Recorded Investment in Impaired Loans	33,000	[3]	2,042,000	[3]
Interest Income Recognized	28,000		56,000
Impaired Loans [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	251,981,000		309,814,000
Recorded Investment in Impaired Loans	208,147,000		262,874,000
Related Charge-offs	43,834,000		46,940,000
Related Specific Allowance	12,394,000		13,625,000
Average Recorded Investment in Impaired Loans	175,484,000	[3]	262,433,000	[3]
Interest Income Recognized	2,852,000		4,220,000
Impaired Loans [Member] | Originated Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	141,540,000		166,915,000
Recorded Investment in Impaired Loans	101,312,000		124,429,000
Related Charge-offs	40,228,000		42,486,000
Related Specific Allowance	10,780,000		11,612,000
Average Recorded Investment in Impaired Loans	72,232,000	[3]	121,222,000	[3]
Interest Income Recognized	1,424,000		1,921,000
Impaired Loans [Member] | Purchased Loans And Leases [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	110,441,000	[4]	142,899,000	[5]
Recorded Investment in Impaired Loans	106,835,000	[4]	138,445,000	[5]
Related Charge-offs	3,606,000	[4]	4,454,000	[5]
Related Specific Allowance	1,614,000	[4]	2,013,000	[5]
Average Recorded Investment in Impaired Loans	103,252,000	[3],[4]	141,211,000	[3],[5]
Interest Income Recognized	1,428,000	[4]	2,299,000	[5]
Impaired Loans [Member] | Commercial, Financial, And Agricultural [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	29,692,000		38,060,000
Recorded Investment in Impaired Loans	26,778,000		33,913,000
Related Charge-offs	2,914,000		4,147,000
Related Specific Allowance	6,116,000		3,008,000
Average Recorded Investment in Impaired Loans	26,739,000	[3]	35,209,000	[3]
Interest Income Recognized	314,000		544,000
Impaired Loans [Member] | Real Estate - Construction [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	16,286,000		33,053,000
Recorded Investment in Impaired Loans	10,650,000		21,503,000
Related Charge-offs	5,636,000		11,550,000
Related Specific Allowance	655,000		1,819,000
Average Recorded Investment in Impaired Loans	11,550,000	[3]	20,546,000	[3]
Interest Income Recognized	128,000		368,000
Impaired Loans [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	45,400,000		65,807,000
Recorded Investment in Impaired Loans	43,805,000		62,798,000
Related Charge-offs	1,595,000		3,009,000
Related Specific Allowance	3,209,000		4,753,000
Average Recorded Investment in Impaired Loans	23,098,000	[3]	63,073,000	[3]
Interest Income Recognized	512,000		851,000
Impaired Loans [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	159,524,000		170,902,000
Recorded Investment in Impaired Loans	125,863,000		142,668,000
Related Charge-offs	33,661,000		28,234,000
Related Specific Allowance	2,300,000		3,827,000
Average Recorded Investment in Impaired Loans	114,064,000	[3]	141,549,000	[3]
Interest Income Recognized	1,870,000		2,401,000
Impaired Loans [Member] | Consumer [Member]
Financing Receivable Impaired [Line Items]
Unpaid Principal Balance	1,079,000		1,992,000
Recorded Investment in Impaired Loans	1,051,000		1,992,000
Related Charge-offs	28,000		0
Related Specific Allowance	114,000		218,000
Average Recorded Investment in Impaired Loans	33,000	[3]	2,056,000	[3]
Interest Income Recognized	$ 28,000		$ 56,000

[1] $34,632 of the $148,312 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 $26,512.

[2] $43,363 of the $195,033 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 $25,986.

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

[4] $5,163 of the $106,835 purchased impaired loans were subsequently impaired after being acquired.

[5] $9,498 of the $138,445 purchased impaired loans were subsequently impaired after being acquired.