Pensions and Postretirement Benefits Other than Pensions - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 393	$ 487	$ 1,180	$ 1,461
Interest cost	2,472	2,313	7,414	6,938
Amortization of prior service cost	(102)	(135)	(306)	(406)
Net periodic benefit cost	2,763	2,665	8,288	7,993
United States | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,244	2,590	6,732	7,770
Interest cost	9,875	9,210	29,624	27,629
Expected return on plan assets	(11,741)	(13,508)	(35,776)	(40,525)
Amortization of actuarial loss	8,279	8,235	24,843	24,706
Net periodic benefit cost	8,657	6,527	25,423	19,580
International | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	2,669	2,722	8,273	8,469
Expected return on plan assets	(2,788)	(2,945)	(8,642)	(9,161)
Amortization of actuarial loss	898	1,040	2,782	3,235
Net periodic benefit cost	$ 779	$ 817	$ 2,413	$ 2,543