|
Summary of Significant Accounting Policies - Additional Information (Detail)
Share data in Millions, unless otherwise specified |
3 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Mar. 31, 2012
USD ($)
|
Dec. 31, 2011
USD ($)
|
Mar. 31, 2012
Fair Value, Measurements, Recurring
USD ($)
|
Dec. 31, 2011
Fair Value, Measurements, Recurring
USD ($)
|
Mar. 31, 2012
United Kingdom Subsidiary
EUR (€)
Contract
|
Mar. 31, 2012
Fixed Rate Debt
USD ($)
|
Dec. 31, 2011
Fixed Rate Debt
USD ($)
|
Mar. 31, 2012
Stock Options
|
Mar. 31, 2011
Stock Options
|
||||
| Significant Accounting Policies [Line Items] | ||||||||||||
| Antidilutive stock options excluded from computation of earnings per share | 0.1 | 1.2 | ||||||||||
| Fair value of debt | $ 1,080,000,000 | $ 1,090,000,000 | ||||||||||
| Carrying value of debt | 969,000,000 | 999,200,000 | 970,000,000 | 970,000,000 | ||||||||
| Aggregate notional amount of unsettled cash flow hedges | 1,200,000 | |||||||||||
| Number of cash flow hedges | 3 | |||||||||||
| Fair value of interest rate swaps | 14,300,000 | [1] | 14,800,000 | |||||||||
| Variable interest maximum exposure to loss | $ 8,700,000 | |||||||||||
|
||||||||||||