Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Service costs	$ 43	$ 45
Interest costs	1,239	1,781
Amortization of net actuarial loss	1,690	1,320
Amortization of prior service credit	(326)	(777)
Net periodic costs	$ 2,646	$ 2,369