Derivative Instruments and Hedging Activities - Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities (Detail) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives not Designated as Hedging Instruments
Gross amounts recognized	$ 11,295	$ 13,203
Gross amounts offset	0	(222)
Net amounts presented in the Consolidated Balance Sheets	11,295	12,981
Net Amount	11,295	12,981
Gross amounts recognized	11,276	13,175
Gross amounts offset	0	(222)
Net amounts presented in the Consolidated Balance Sheets	11,276	12,953
Collateral Already Posted, Aggregate Fair Value	(12,573)	(12,059)
Net Amount	$ (1,297)	$ 894