Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Service costs	$ 44	$ 70	$ 134	$ 211
Interest costs	1,781	2,280	5,343	6,838
Amortization of net actuarial loss	1,321	916	3,961	2,746
Amortization of prior service credit	(777)	(1,018)	(2,331)	(3,053)
Net periodic costs	$ 2,369	$ 2,248	$ 7,107	$ 6,742