Pensions and Other Post-retirement Benefits - Schedule of Defined Benefit Pension Plans and Other Postretirement Benefits Plan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Funded Status
Noncurrent assets	$ 97,545	$ 75,066
Noncurrent liabilities	(208,068)	(186,697)
Pension Benefits
Change in Benefit Obligations
Benefit obligations at January 1	603,551	525,520
Service cost	12,094	10,342	$ 11,125
Interest cost	14,905	18,803	17,214
Participant contributions	396	470
Plan amendments	(430)	0
Actuarial losses(a)	54,606	81,132
Benefits paid	(24,496)	(24,452)
Curtailments	1,559	0
Settlements	(506)	(7,265)
Currency translation	12,296	(999)
Benefit obligations at December 31	670,857	603,551	525,520
Change in Plan Assets
Fair value of plan assets at January 1	515,858	443,112
Actual return on plan assets	87,769	98,210
Employer contributions	5,596	5,537
Participant contributions	396	470
Settlements	(506)	(7,265)
Benefits paid	24,496	24,452
Administrative expenses paid	(172)	(297)
Currency translation	2,377	543
Fair value of plan assets at December 31	586,822	515,858	443,112
Funded Status
Funded status at December 31	(84,035)	(87,693)
Unrecognized transition losses	4	4
Unrecognized prior service credit	1,717	1,572
Unrecognized net actuarial losses	169,028	183,733
Net amount recognized	86,714	97,616
Noncurrent assets	97,545	75,066
Current liabilities	(6,600)	(5,944)
Noncurrent liabilities	(174,980)	(156,815)
Net amount recognized	(84,035)	(87,693)
Amounts Recognized in Accumulated Other Comprehensive Loss
Net actuarial losses	169,028	183,733
Prior service cost (credit)	1,717	1,572
Unrecognized net initial obligation	4	4
Total (before tax effects)	170,749	185,309
Accumulated Benefit Obligations for all Defined Benefit Plans	619,167	558,183
Other Benefits
Change in Benefit Obligations
Benefit obligations at January 1	28,151	28,477
Service cost	396	354	369
Interest cost	716	996	793
Participant contributions	370	380
Plan amendments	0	0
Actuarial losses(a)	5,284	1,319
Benefits paid	(2,692)	(3,375)
Curtailments	0	0
Settlements	0	0
Currency translation	0	0
Benefit obligations at December 31	32,225	28,151	28,477
Change in Plan Assets
Fair value of plan assets at January 1	0	0
Actual return on plan assets	0	0
Employer contributions	2,322	2,995
Participant contributions	370	380
Settlements	0	0
Benefits paid	2,692	3,375
Administrative expenses paid	0	0
Currency translation	0	0
Fair value of plan assets at December 31	0	0	$ 0
Funded Status
Funded status at December 31	(32,225)	(28,151)
Unrecognized transition losses	0	0
Unrecognized prior service credit	(1,125)	(1,519)
Unrecognized net actuarial losses	16,686	12,547
Net amount recognized	(16,664)	(17,123)
Noncurrent assets	0	0
Current liabilities	(2,849)	(2,406)
Noncurrent liabilities	(29,376)	(25,745)
Net amount recognized	(32,225)	(28,151)
Amounts Recognized in Accumulated Other Comprehensive Loss
Net actuarial losses	16,686	12,547
Prior service cost (credit)	(1,125)	(1,519)
Unrecognized net initial obligation	0	0
Total (before tax effects)	15,561	11,028
Accumulated Benefit Obligations for all Defined Benefit Plans	$ 0	$ 0