Loans - Summary of Impaired Financial Receivables (Summary of Covered Impaired Loans) (Detail) (USD $)	6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings not included above	$ 21,100,000	$ 20,600,000	$ 20,900,000
Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	46,138,000	88,939,000	69,152,000
Troubled debt restructurings not included above	9,221,000	10,253,000	8,409,000
Total impaired loans	55,359,000	99,192,000	77,561,000
Impaired loans not requiring a related allowance	55,359,000	99,192,000	77,561,000
Impaired loans requiring a related allowance
Allowance related to impaired loans
Average investment in impaired loans	70,932,000	104,473,000	94,873,000
Interest income recognized on impaired loans	214,000	784,000	968,000
Foregone interest income on impaired loans	$ 94,000	$ 242,000	$ 330,000