Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 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	37,900,000
Total amount of all impaired loans	48,654,000	52,856,000
Commercial real estate impaired loans needing current appraisals	700,000
Commercial real estate impaired loans current appraisals	22,200,000
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	22,200,000
Percentage of total impaired loans comprised	45.70%
Total amount of all impaired loans	22,219,000	26,968,000
Charge offs on loans	$ 8,800,000