Loans and Allowance for Loan Losses - Summary of Impaired Financial Receivables (Analysis of Covered Impaired Loans) (Detail) (Covered Loans [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	$ 106,690	$ 176,828
Recorded Investment With No Allowance	91,395	132,802	179,883
Recorded Investment With Allowance
Total Recorded Investment	91,395	132,802	179,883
Related Allowance
Average Recorded Investment	110,830	163,825	138,950
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	9,680	15,888
Recorded Investment With No Allowance	7,270	10,802
Recorded Investment With Allowance
Total Recorded Investment	7,270	10,802
Related Allowance
Average Recorded Investment	8,696	12,506
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	20,915	30,979
Recorded Investment With No Allowance	18,037	22,948
Recorded Investment With Allowance
Total Recorded Investment	18,037	22,948
Related Allowance
Average Recorded Investment	21,794	29,970
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	46,612	84,124
Recorded Investment With No Allowance	40,749	62,415
Recorded Investment With Allowance
Total Recorded Investment	40,749	62,415
Related Allowance
Average Recorded Investment	51,584	78,790
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	29,089	45,464
Recorded Investment With No Allowance	24,998	36,335
Recorded Investment With Allowance
Total Recorded Investment	24,998	36,335
Related Allowance
Average Recorded Investment	28,452	42,061
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	394	373
Recorded Investment With No Allowance	341	302
Recorded Investment With Allowance
Total Recorded Investment	341	302
Related Allowance
Average Recorded Investment	$ 304	$ 498