Fair Value Disclosures - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Assets transfer between Level 2 and Level 3	$ 0	$ 0	$ 0	$ 0
Impaired loans carrying value	21,788,000	22,093,000	21,788,000	22,093,000	$ 20,194,000
Impaired loans valuation reserves	4,645,000		4,645,000
Impaired loans net fair value	17,143,000		17,143,000
Other real estate owned, total	$ 360,000	$ 1,185,000	$ 360,000	$ 1,185,000	$ 943,000
Minimum [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Debt discounts, percentage			5.00%
Maximum [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Debt discounts, percentage			25.00%