Employee and Retiree Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension and Other Postretirement Benefits Disclosure [Line Items]
Future annual rate of increase in cost of health care for 2012 to measure postretirement benefit obligations	7.80%
Ultimate rate of health care cost in 2020 and thereafter	5.00%
Provisions of the March 2010 Health Care Reform	In March 2010, the United States Congress enacted a health care reform law. Along with other provisions, the law (a) eliminates the tax free status of federal subsidies to companies with qualified retiree prescription drug plans that are actuarially equivalent to Medicare Part D plans beginning in 2013; (b) imposes a 40% excise tax on high-cost health plans as defined in the law beginning in 2018; (c) eliminates lifetime or annual coverage limits and required coverage for preventative health services beginning in September 2010; and (d) imposed a fee of $2 (subsequently adjusted for inflation) for each person covered by a health insurance policy beginning in September 2010.
Excise tax rate imposed on high-cost health plans beginning 2018	40.00%
Government imposed fee for each person covered by health insurance policy	$ 2
Asset performance compared to a benchmark return, percent targeted to outperform the benchmark over three years	0.75%
Amounts charged to expense for U.S. and U.K. plans	10,725,000	11,467,000	11,617,000
Allocations of plan assets to be invested in equity securities, minimum	40.00%
Allocations of plan assets to be invested in equity securities, maximum	70.00%
Allocations of plan assets to be invested in fixed income securities, minimum	30.00%
Allocations of plan assets to be invested in fixed income securities, maximum	60.00%
Allocations of plan assets to be invested in cash and equivalents, minimum	0.00%
Allocations of plan assets to be invested in cash and equivalents, maximum	15.00%
Allocations of plan assets to be invested in long/short equity, maximum	10.00%
Equity securities minimum market capitalization	100,000,000
Weighted average expected return on plan assets	6.48%
Fixed Income Securities
Pension and Other Postretirement Benefits Disclosure [Line Items]
Fixed income portfolio, maximum average maturity years	11
Basis used to determine expected return on plan asset, percentage of expected return (expense)	4.53%
US long/short equity fund
Pension and Other Postretirement Benefits Disclosure [Line Items]
Allocations of plan assets to be invested in long/short equity, minimum	0.00%
Allocations of plan assets to be invested in long/short equity, maximum	15.00%
Equity Securities
Pension and Other Postretirement Benefits Disclosure [Line Items]
Basis used to determine expected return on plan asset, percentage of expected return (expense)	8.29%
Average expected investment expense, net
Pension and Other Postretirement Benefits Disclosure [Line Items]
Basis used to determine expected return on plan asset, percentage of expected return (expense)	0.28%
Foreign Other Postretirement Benefit Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to benefit plans	52,000
Expected benefit plan contributions to be made during next year	45,000
Funded Retirement Plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Weighted average expected return on plan assets	5.06%
Domestic postretirement benefits plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to benefit plans	4,011,000
Expected benefit plan contributions to be made during next year	5,790,000
Domestic postretirement benefits plan | Commingled trust fund | Minimum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Domestic plan, commingled trusts waiting periods for withdrawals (in days)	6 days
Domestic postretirement benefits plan | Commingled trust fund | Maximum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Domestic plan, commingled trusts waiting periods for withdrawals (in days)	30 days
Domestic defined benefit pension plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to benefit plans	23,736,000
Expected benefit plan contributions to be made during next year	27,171,000
Foreign Defined Benefit Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to benefit plans	14,621,000
Expected benefit plan contributions to be made during next year	$ 8,311,000
United Kingdom | Foreign Other Postretirement Benefit Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Allocations of plan assets to be invested in equity securities	60.00%
Allocations of plan assets to be invested in fixed income securities	40.00%
Allocations of plan assets to be invested in equity securities, minimum	27.00%
Allocations of plan assets to be invested in equity securities, maximum	98.00%
Allocations of plan assets to be invested in fixed income securities, minimum	25.00%
Allocations of plan assets to be invested in fixed income securities, maximum	60.00%
Allocations of plan assets to be invested in cash and equivalents, maximum	5.00%
Description of equity and fixed income securities allocation	Approximately one-half of the equity allocation is to be invested in U.K. securities and the reminder split between North American, European, Japanese and other Pacific Basin securities. A minimum of 95% of the fixed income allocation is to be invested in U.K. securities with up to 5% in international or high yield bonds.
Canada | Foreign Other Postretirement Benefit Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Allocations of plan assets to be invested in equity securities	60.00%
Allocations of plan assets to be invested in fixed income securities	35.00%
Allocations of plan assets to be invested in equity securities, minimum	40.00%
Allocations of plan assets to be invested in equity securities, maximum	75.00%
Allocations of plan assets to be invested in fixed income securities, minimum	25.00%
Allocations of plan assets to be invested in fixed income securities, maximum	45.00%
Allocations of plan assets to be invested in cash and equivalents, minimum	0.00%
Allocations of plan assets to be invested in cash and equivalents, maximum	15.00%
Allocations of plan assets to be invested in cash and equivalents	5.00%