Loans - Summary of Covered Loans According to Loan Type (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	$ 209,598	$ 271,279	$ 331,250
Commercial, Financial & Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	17,666	21,467	25,209
Real Estate - Construction & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	15,002	23,447	31,600
Real Estate - Commercial & Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	111,772	147,627	188,643
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	64,982	78,520	85,518
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	$ 176	$ 218	$ 280