Employee Benefits - Pension Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Pension expense	$ 10,260	$ 9,217	$ 6,023
Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Pension expense	600	500	$ 700
Unfunded liability	$ 12,100	$ 12,600