Loans - Summary of Impaired Financial Receivables (Analysis of Covered Impaired Loans) (Detail) (Covered Loans [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	$ 94,908	$ 296,665	$ 106,690
Recorded Investment With No Allowance	82,556	120,107	91,395
Recorded Investment With Allowance
Total Recorded Investment	82,556	120,107	91,395
Related Allowance
Average Recorded Investment	86,976	127,507	110,830
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	12,143	24,301	9,680
Recorded Investment With No Allowance	10,039	8,754	7,270
Recorded Investment With Allowance
Total Recorded Investment	10,039	8,754	7,270
Related Allowance
Average Recorded Investment	8,655	9,778	8,696
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	20,704	78,421	20,915
Recorded Investment With No Allowance	18,034	23,978	18,037
Recorded Investment With Allowance
Total Recorded Investment	18,034	23,978	18,037
Related Allowance
Average Recorded Investment	18,036	23,607	21,794
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	36,664	139,197	46,612
Recorded Investment With No Allowance	31,746	55,822	40,749
Recorded Investment With Allowance
Total Recorded Investment	31,746	55,822	40,749
Related Allowance
Average Recorded Investment	36,247	60,026	51,584
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	25,230	54,422	29,089
Recorded Investment With No Allowance	22,604	31,310	24,998
Recorded Investment With Allowance
Total Recorded Investment	22,604	31,310	24,998
Related Allowance
Average Recorded Investment	23,801	33,823	28,452
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	167	324	394
Recorded Investment With No Allowance	133	243	341
Recorded Investment With Allowance
Total Recorded Investment	133	243	341
Related Allowance
Average Recorded Investment	$ 237	$ 273	$ 304