Defined Benefit Plans - Net Periodic Cost (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Retirement Benefits [Abstract]
Expected return on plan assets, net of expenses	$ (3,072)	$ (2,693)
Interest cost on projected benefit obligation	1,252	1,618
Net amortization and deferral	1,330	1,406
Net periodic expense (benefit)	$ (490)	$ 331