Asset-Backed Financing (Narrative) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 25, 2011	Sep. 30, 2012	Sep. 30, 2012 SPEs [Member]	Dec. 31, 2011 SPEs [Member]	Sep. 25, 2011 SPEs [Member]
Variable Interest Entity [Line Items]
Secured notes' contractual maturity period, start				Jan. 01, 2012
Secured notes issued	$ 675,300,000	$ 573,400,000	$ 89,500,000
Unaccreted premium	1,500,000		1,500,000
Asset-backed securities expiration date	9/13/2013
Total aggregate commitment	600,000,000		600,000,000
Borrowings outstanding under conduit facility					$ 0	$ 0