Loans and Allowance for Loan Losses - Summary of Impaired Financial Receivables (Summary of Covered Impaired Loans) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings not included above	$ 20,900,000	$ 23,900,000
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
Troubled debt restructurings not included above	22,243,000	17,090,000	19,884,000
Total impaired loans	91,395,000	132,802,000	179,883,000
Impaired loans not requiring a related allowance	91,395,000	132,802,000	179,883,000
Impaired loans requiring a related allowance
Allowance related to impaired loans
Average investment in impaired loans	110,830,000	163,825,000	138,950,000
Interest income recognized on impaired loans	968,000	849,000	526,000
Foregone interest income on impaired loans	$ 330,000	$ 491,000	$ 202,000