Loans and Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2014		Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2014 Forgiveness Of Principal	Sep. 30, 2013 Payment Deferrals Granted		Sep. 30, 2014 Payment Deferrals Granted	Sep. 30, 2013 Payment Deferrals Granted
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Deferred Income	$ 95,000,000		$ 95,000,000		$ 89,000,000
Loans modified in TDRs	10,300,000		10,300,000		22,433,000
Unfunded commitments available for funding	800,000		800,000
Loans modified in TDRs during the period	$ 496,000	[1]	$ 8,462,000	[1]		$ 1,300,000	$ 7,337,000	[1]	$ 7,100,000	$ 9,653,000	[1]

[1] There were no partial charge-offs on loans classified as TDRs for the three and nine months ended September 30, 2014. There were partial charge-offs of $1.2 million and $2.4 million on loans classified as TDRs for the three and nine months ended September 30, 2013