Allowance for Loan Losses - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Evaluation for impairment of substandard and nonaccrual commercial loans	$ 500,000.0
Commercial real estate impaired loans fair value	34,700,000
Total amount of all impaired loans	46,209,000	52,856,000
Commercial real estate impaired loans needing current appraisals	600,000
Minimum [Member]
Financing Receivable, Impaired [Line Items]
Loans considered nonperforming (in days)	90 days
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Commercial real estate impaired loans fair value	21,200,000
Percentage of total impaired loans comprised	46.00%
Total amount of all impaired loans	21,228,000	26,968,000
Charge offs on loans	$ 7,900,000