Loans - Summary of Impaired Financial Receivables (Summary of Purchased Non-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
Purchased Non-Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	15,770,000		6,659,000
Troubled debt restructurings not included above
Total impaired loans	15,770,000		6,659,000
Impaired loans not requiring a related allowance	15,770,000		6,659,000
Impaired loans requiring a related allowance
Allowance related to impaired loans
Average investment in impaired loans	12,582,000		128,000
Interest income recognized on impaired loans	16,000
Foregone interest income on impaired loans	$ 158,000