Loans and Allowance for Loan Losses - Summary of Financial Receivable Nonaccrual Basis (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Excluding Purchased Non-Covered and Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 29,203,000	$ 38,885,000	$ 70,823,000	$ 79,289,000	$ 96,131,000
Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	6,659,000
Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	69,152,000	115,712,000	159,999,000	88,153,000	25,791,000
Commercial, Financial and Agricultural [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	4,103,000	4,138,000	3,987,000	8,648,000	4,774,000
Commercial, Financial and Agricultural [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	11,000
Commercial, Financial and Agricultural [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	7,257,000	10,765,000	11,952,000	5,756,000	1,398,000
Real Estate - Construction and Development [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	3,971,000	9,281,000	15,020,000	7,887,000	15,787,000
Real Estate - Construction and Development [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	325,000
Real Estate - Construction and Development [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	14,781,000	20,027,000	30,977,000	25,810,000	9,155,000
Real Estate - Commercial and Farmland [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	8,566,000	11,962,000	35,385,000	55,170,000	67,172,000
Real Estate - Commercial and Farmland [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	1,653,000
Real Estate - Commercial and Farmland [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	33,495,000	55,946,000	75,458,000	29,519,000	8,109,000
Real Estate - Residential [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	12,152,000	12,595,000	15,498,000	6,376,000	6,965,000
Real Estate - Residential [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	4,658,000
Real Estate - Residential [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	13,278,000	28,672,000	41,139,000	25,946,000	4,602,000
Consumer Installment Loans [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	411,000	909,000	933,000	1,208,000	1,433,000
Consumer Installment Loans [Member] | Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	12,000
Consumer Installment Loans [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 341,000	$ 302,000	$ 473,000	$ 1,122,000	$ 2,527,000