Restructuring Activities - Additional Information (Detail) (Green River Victorville Facilities, USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Green River Victorville Facilities
Restructuring Cost and Reserve [Line Items]
Company's investment in capital expenditure		$ 11
Expected investment in capital expenditures, total	35
Expected investment in transition expenses	6
Accelerated depreciation expense in cost of sales	0.6	2.3
Transition costs recorded in cost of sales	$ 1.3	$ 1.2