Pension and Other Postretirement Benefits - Asset Categories Based on the Nature and Risks of the Plan Assets (Detail) £ in Thousands, $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 GBP (£)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Foreign Defined Benefits Pension Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	$ 57,900	£ 43,913	$ 49,651	£ 38,991
Defined Benefit Pension Plan [Member] | U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	195,667		182,541		$ 199,138
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	89,660		44,997
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Discretionary [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	4,054		891
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Staples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	3,368		602
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Energy [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	1,405		415
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	3,612		1,075
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Healthcare [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	6,952		1,718
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Industrials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	6,941		780
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Information Technology [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,443		1,632
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Materials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	844		177
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	51,259		36,883
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Real Estate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	272
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Telecommunications [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	2,994		560
Defined Benefit Pension Plan [Member] | U.S. [Member] | Equity Securities, U.S., Utilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	516		264
Defined Benefit Pension Plan [Member] | U.S. [Member] | Fixed Income Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	79,594		80,725
Defined Benefit Pension Plan [Member] | U.S. [Member] | Fixed Income Securities, Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	45,289		44,786
Defined Benefit Pension Plan [Member] | U.S. [Member] | Fixed Income Securities, Treasury Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	15,751		25,605
Defined Benefit Pension Plan [Member] | U.S. [Member] | Fixed Income Securities, Agency Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	10,752		10,334
Defined Benefit Pension Plan [Member] | U.S. [Member] | Fixed Income Securities, Mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,802
Defined Benefit Pension Plan [Member] | U.S. [Member] | Alternative Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	19,341		23,673
Defined Benefit Pension Plan [Member] | U.S. [Member] | Alternative Investments, Managed Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	19,341		23,673
Defined Benefit Pension Plan [Member] | U.S. [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,072		33,146
Defined Benefit Pension Plan [Member] | U.S. [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,038		33,146
Defined Benefit Pension Plan [Member] | U.S. [Member] | Other, Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	34
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	57,900		49,651		56,419
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	72		156
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	8,165		24,594
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	4,874		3,949
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (International) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	3,291		20,645
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member] | Fixed-Income Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	43,168		17,332
Defined Benefit Pension Plan [Member] | Foreign Defined Benefits Pension Plans [Member] | Alternative Investments, Absolute Return Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	6,495		7,569
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	120,351		103,748
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	89,660		44,997
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Discretionary [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	4,054		891
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Staples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	3,368		602
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Energy [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	1,405		415
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	3,612		1,075
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Healthcare [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	6,952		1,718
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Industrials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	6,941		780
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Information Technology [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,443		1,632
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Materials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	844		177
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	51,259		36,883
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Real Estate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	272
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Telecommunications [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	2,994		560
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Equity Securities, U.S., Utilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	516		264
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Fixed Income Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	23,553		25,605
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Fixed Income Securities, Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Fixed Income Securities, Treasury Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	15,751		25,605
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Fixed Income Securities, Agency Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Fixed Income Securities, Mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,802
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Alternative Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Alternative Investments, Managed Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,138		33,146
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	7,038		33,146
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. [Member] | Other, Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	100
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	72		156
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	72		156
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (International) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member] | Fixed-Income Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Foreign Defined Benefits Pension Plans [Member] | Alternative Investments, Absolute Return Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	56,041		55,120
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Discretionary [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Staples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Energy [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Healthcare [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Industrials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Information Technology [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Materials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Real Estate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Telecommunications [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Equity Securities, U.S., Utilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Fixed Income Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	56,041		55,120
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Fixed Income Securities, Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	45,289		44,786
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Fixed Income Securities, Treasury Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Fixed Income Securities, Agency Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	10,752		10,334
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Fixed Income Securities, Mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Alternative Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Alternative Investments, Managed Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. [Member] | Other, Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	51,333		41,926
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	8,165		24,594
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	4,874		3,949
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (International) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	3,291		20,645
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member] | Fixed-Income Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	43,168		17,332
Defined Benefit Pension Plan [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Defined Benefits Pension Plans [Member] | Alternative Investments, Absolute Return Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	19,275		23,673
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Discretionary [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Consumer Staples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Energy [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Healthcare [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Industrials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Information Technology [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Materials [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Real Estate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Telecommunications [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Equity Securities, U.S., Utilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Fixed Income Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Fixed Income Securities, Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Fixed Income Securities, Treasury Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Fixed Income Securities, Agency Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Fixed Income Securities, Mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Alternative Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	19,341		23,673		49,838
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Alternative Investments, Managed Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	19,341		23,673
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	(66)		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. [Member] | Other, Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	(66)
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	6,495		7,569
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member] | Other (Primarily Cash and Cash Equivalents) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member] | Equity Securities, Commingled Funds (International) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member] | Fixed-Income Securities, Commingled Funds (U.K.) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	0		0
Defined Benefit Pension Plan [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Defined Benefits Pension Plans [Member] | Alternative Investments, Absolute Return Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of plan assets	$ 6,495		$ 7,569		$ 9,637	$ 7,569