Allowance for Loan Losses - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Financing Receivable, Impaired [Line Items]
Evaluation for impairment of substandard and nonaccrual commercial loans	$ 500,000.0
Minimum [Member]
Financing Receivable, Impaired [Line Items]
Loans considered nonperforming (in days)	90 days