Investments - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 30, 2013 AFS_security	Mar. 31, 2012	Dec. 29, 2012
Investments, Debt and Equity Securities [Abstract]
Total realized gains on sales of AFS securities	$ 6,862,000	$ 2,549,000
Total realized losses on sales of AFS securities	4,203,000	2,311,000
Other-than-temporary impairment losses	0	0
Number of AFS securities issues contributing to total unrealized loss	242
Total, unrealized Losses	$ 9,993,000		$ 15,500,000

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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