Loans and Allowance for Loan Losses - Summary of Purchased Non-Covered Loans According to Loan Type (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	$ 22,377	$ 23,593
Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	448,753
Commercial, Financial and Agricultural [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	32,141
Real Estate - Construction and Development [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	31,176
Real Estate - Commercial and Farmland [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	179,898
Real Estate - Residential [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	200,851
Consumer Installment Loans [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-covered loans	$ 4,687