Cash, Cash Equivalents, and Investments (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 05, 2015	Jun. 29, 2014	Jul. 05, 2015	Jun. 29, 2014
Cash and Cash Equivalents [Abstract]
Gross realized gains on sale of investments	$ 210,000	$ 117,000	$ 408,000,000	$ 629,000,000
Gross realized losses on sale of investments	18,000	$ 12,000	187,000,000	$ 23,000,000
Maximum amount committed to invest in limited partnership			20,500,000
Contribution to limited partnership	19,886,000		$ 19,886,000
Investment expiration date			Dec. 31, 2015
Remaining amount of commitment in limited partnership	$ 614,000		$ 614,000
Number of contributions made during the period			0
Distributions from Partnership during period			$ 0