Investment Securities - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) Bond	Mar. 31, 2015	Dec. 31, 2015 USD ($) Bond
Schedule of Available-for-sale Securities [Line Items]
Average yields (taxable equivalent) on securities	3.03%	2.46%
Market value of securities	$ 8,800		$ 8,600
Securities sold under repurchase agreements	6,012		7,161	[1]
Company's investment in Federal Home Loan Bank stock	1,900		2,000
Company's investment in Federal Reserve Bank stock	$ 505		$ 505
US Government Agencies
Schedule of Available-for-sale Securities [Line Items]
Bonds with unrealized loss positions | Bond	8		24
Municipal Securities
Schedule of Available-for-sale Securities [Line Items]
Bonds with unrealized loss positions | Bond	5		17
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Bonds with unrealized loss positions | Bond	1		1

[1] Derived from Audited December 31, 2015 Financial Statements.