Cash, Cash Equivalents, and Investments (Detail) - USD ($)	3 Months Ended
	Apr. 03, 2016	Apr. 05, 2015
Cash and Cash Equivalents [Abstract]
Gross realized gains on sale of investments	$ 84,000	$ 197,000
Gross realized losses on sale of investments	97,000	$ 168,000
Maximum amount committed to invest in limited partnership	20,500,000
Contribution to limited partnership	$ 19,886,000
Investment expiration date	Dec. 31, 2017
Remaining amount of commitment in limited partnership	$ 614,000
Number of contributions made during the period	$ 0