Loans - Summary of Troubled Debt Restructurings by Loan Class, Classified Separately under Restructured Terms (Detail) (Covered Loans [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2014 Contract	Dec. 31, 2013 Contract	Jun. 30, 2013 Contract
Loans Currently Paying Under Restructured Terms [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	85	66	65
Troubled debt restructuring loans	$ 8,542	$ 6,592	$ 8,599
Loans Currently Paying Under Restructured Terms [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1	1
Troubled debt restructuring loans	24	27	40
Loans Currently Paying Under Restructured Terms [Member] | Real Estate - Construction and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts		1	2
Troubled debt restructuring loans		16	2,159
Loans Currently Paying Under Restructured Terms [Member] | Real Estate - Commercial and Farmland [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	7	5	5
Troubled debt restructuring loans	1,217	713	592
Loans Currently Paying Under Restructured Terms [Member] | Real Estate - Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	76	58	57
Troubled debt restructuring loans	7,297	5,830	5,808
Loans Currently Paying Under Restructured Terms [Member] | Consumer Installment Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1
Troubled debt restructuring loans	4	6
Loans That Have Defaulted Under Restructured Terms [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	14	21	9
Troubled debt restructuring loans	1,276	2,503	1,805
Loans That Have Defaulted Under Restructured Terms [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts		1
Troubled debt restructuring loans		40
Loans That Have Defaulted Under Restructured Terms [Member] | Real Estate - Construction and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1		1
Troubled debt restructuring loans	14		11
Loans That Have Defaulted Under Restructured Terms [Member] | Real Estate - Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	13	20	8
Troubled debt restructuring loans	$ 1,262	$ 2,463	$ 1,794