Securities - Trading Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 4,576	$ 4,505
Corporate Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	3,389	3,044
Mutual Funds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	750	999
Certificates of Deposit [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	253	253
Corporate Notes and Bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	130	155
U.S. Government Sponsored Entities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 54	$ 54