Pension and Postretirement Benefits other than Pensions - Net Periodic Benefit Cost of Defined Benefit Plans and Other Postretirement Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Domestic Plan [Member] | Pension Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	$ 189	$ 213	$ 378	$ 426
Interest cost	2,952	2,706	5,904	5,412
Expected return on plan assets	(4,155)	(4,354)	(8,310)	(8,708)
Amortization of prior service cost credit and recognized actuarial gain (loss)	781	601	1,562	1,202
Net periodic benefit (income) cost	(233)	(834)	(466)	(1,668)
Domestic Plan [Member] | Other Postretirement Benefits Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	25	77	66	154
Interest cost	202	300	461	600
Amortization of prior service cost credit and recognized actuarial gain (loss)	(566)	(418)	(1,308)	(836)
Other	0	1	0	2
Net periodic benefit (income) cost	(339)	(40)	(781)	(80)
Foreign Plan [Member] | Pension Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	943	1,065	2,054	2,161
Interest cost	1,063	1,050	2,123	2,120
Expected return on plan assets	(591)	(633)	(1,186)	(1,265)
Amortization of prior service cost credit and recognized actuarial gain (loss)	593	668	1,209	1,356
Net periodic benefit (income) cost	2,008	2,150	4,200	4,372
Foreign Plan [Member] | Other Postretirement Benefits Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	91	124	208	250
Interest cost	179	198	382	396
Amortization of prior service cost credit and recognized actuarial gain (loss)	93	77	131	154
Other	0	0	0	0
Net periodic benefit (income) cost	$ 363	$ 399	$ 721	$ 800