Subordinated Debt (Detail) - Subordinated Debt Due May 2025 - USD ($)	12 Months Ended
	Dec. 31, 2015	May. 28, 2015
Debt and Financial Instruments [Line Items]
Debt instrument, face amount	$ 7,000,000	$ 7,000,000
Less: Issuance costs	(156,000)
Proceeds from Debt, Net of Issuance Costs	$ 6,844,000