Defined Benefit Plans - Net Periodic Cost (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Expected return on plan assets, net of expenses	$ (2,890)	$ (2,983)
Interest cost on projected benefit obligation	1,749	2,052
Net amortization and deferral	1,553	1,749
Net periodic expense (benefit)	$ 412	$ 818