Discontinued Operations (Detail) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 25, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Aug. 06, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax impairment charges					$ 115,400,000
Net tax benefit, related to losses estimated in connection with sale					40,000,000
Total tax benefit associated with losses on sale				101,000,000	66,000,000
Uncertain tax benefit reserved against losses estimated in connection with sale of MV				43,500,000	26,000,000
Impairment charges included in operating loss				111,800,000
Additional tax benefits on impairment charges				18,000,000
Advances to affiliate						20,000,000
Cumulative net tax benefit				57,500,000
Tax benefit by reversing reserve			43,500,000
Incremental tax benefit	$ (9,177,000)	$ 2,664,000	$ 7,500,000