Fair Value Disclosures - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets transfer between Level 2 and Level 3	$ 0	$ 0	$ 0	$ 0	$ 0
Impaired loans carrying value	33,712,000		33,712,000
Impaired loans valuation reserves	7,042,000	4,645,000	7,042,000	4,645,000	5,071,000
Impaired loans net fair value	26,670,000		26,670,000
Other real estate owned, total	$ 241,000	$ 360,000	$ 241,000	$ 360,000	$ 153,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt discounts, percentage			5.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt discounts, percentage			25.00%