Employee Benefits - Fair Value Hierarchy of Plan Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S Plans [Member] | Level 3 [Member] | Fair Value Of Plan Assets Before Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0
U.S Plans [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	678,029	$ 602,408	$ 532,381
U.S Plans [Member] | Pension Plan [Member] | Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	997	1,347
U.S Plans [Member] | Pension Plan [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	200,800	80,400
U.S Plans [Member] | Pension Plan [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	342,900	376,000
U.S Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,799	4,431
U.S Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Government & Government Agency Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19,002	19,427
U.S Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104,064	112,137
U.S Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,480	8,460
U.S Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	543,687	456,606
U.S Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fair Value Of Plan Assets Before Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	677,032	601,061
U.S Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Government & Government Agency Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Fair Value Of Plan Assets Before Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,799	4,431
U.S Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Government & Government Agency Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19,002	19,427
U.S Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104,064	112,137
U.S Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,480	8,460
U.S Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Fair Value Of Plan Assets Before Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	133,345	144,455
U.S Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Government & Government Agency Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Fair Value Of Plan Assets Before Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Non-U.S. Plans [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,144,962	1,005,283	$ 896,782
Non-U.S. Plans [Member] | Pension Plan [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31,594	5,921
Non-U.S. Plans [Member] | Pension Plan [Member] | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	65,018	84,542
Non-U.S. Plans [Member] | Pension Plan [Member] | U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,162	24,720
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,213	956
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Small Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	872	738
Non-U.S. Plans [Member] | Pension Plan [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25,391	27,374
Non-U.S. Plans [Member] | Pension Plan [Member] | U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	97	108
Non-U.S. Plans [Member] | Pension Plan [Member] | U S Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43,119	32,013
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	162,947	117,890
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	172,516	183,354
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50,717	33,654
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,636	2,553
Non-U.S. Plans [Member] | Pension Plan [Member] | Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	247,700	152,291
Non-U.S. Plans [Member] | Pension Plan [Member] | Derivative [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91,225	65,016
Non-U.S. Plans [Member] | Pension Plan [Member] | Absolute Return Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96,871	157,894
Non-U.S. Plans [Member] | Pension Plan [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,593	32,513
Non-U.S. Plans [Member] | Pension Plan [Member] | Non-U.S. Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	94,286	83,746
Non-U.S. Plans [Member] | Pension Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,144,962	1,005,283
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	338,387	275,937
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,730	5,921
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	57,461	58,926
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,162	24,720
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,213	956
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Small Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	872	738
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25,391	27,374
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	97	108
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | U S Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	162,947	117,890
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33,596	33,320
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,636	2,553
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Derivative [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Absolute Return Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,086	3,431
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11,191	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 1 [Member] | Non-U.S. Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	693,178	615,151
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,864	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,557	25,616
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Small Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | U S Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43,119	32,013
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	138,920	150,034
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50,717	33,654
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	247,426	152,025
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Derivative [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91,225	65,016
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Absolute Return Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92,785	154,463
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,565	2,330
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 2 [Member] | Non-U.S. Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113,397	114,195
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Small Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | U S Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Treasuries/Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	274	266
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Derivative [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Absolute Return Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,837	30,183
Non-U.S. Plans [Member] | Pension Plan [Member] | Level 3 [Member] | Non-U.S. Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 94,286	$ 83,746