Employee Benefit Plans - Reclassifications from Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Amortization of actuarial loss and prior service costs-total before tax	$ 887
Tax benefit	(330)	$ 156	$ 408
Net of tax	$ 557	$ (263)	$ (685)