Employee Benefit Plans - Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plan [Line Items]
Net actuarial loss	$ (1,773)	$ (1,635)
Tax effect	620	572
Other comprehensive income (loss)	(1,153)	(1,063)	$ (1,084)	$ (981)
Employee Benefit Plan [Member]
Employee Benefit Plan [Line Items]
Other comprehensive income (loss)	$ (1,153)	$ (1,063)