Property Plant and Equipment - Additional Information (Detail) (Property Plant and Equipment, USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Property Plant and Equipment
Component of Operating Other Cost and Expense [Line Items]
Depreciation of property, plant and equipment	$ 31.3	$ 36.6	$ 62.6	$ 72.0