Schedule of Net Periodic Benefit Costs (Detail) - Pension Benefits - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net Period Benefit Cost Assumptions [Line Items]
Service cost	$ (26)	$ (44)	$ 14	$ 12
Interest cost	2,273	914	2,498	1,847
Expected return on plan assets	(2,058)	(513)	(2,094)	(1,076)
Administrative expenses	(11)	(3)	12	7
Settlement loss	323	21	831	92
Amortization of net actuarial losses	35		(9)
Net periodic pension cost	$ 536	$ 375	$ 1,252	$ 882