Investments - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 29, 2012 Securities	Sep. 24, 2011	Sep. 29, 2012 Securities	Sep. 24, 2011	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Total realized gains on sales of AFS securities	$ 9,209,000	$ 7,260,000	$ 18,986,000	$ 29,996,000
Total realized losses on sales of AFS securities	5,722,000	8,148,000	11,097,000	10,324,000
Other-than-temporary impairment losses		6,082,000		6,082,000
Total, unrealized Losses	9,744,000		9,744,000		19,357,000
Number of AFS securities issues contributing to total unrealized loss	200		200
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairment losses		6,082,000		6,082,000
Total, unrealized Losses	$ 9,691,000		$ 9,691,000		$ 14,274,000