Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013
Fair Value Disclosures [Abstract]
Balance at beginning of the year	$ 2,588	$ 2,588
Transfers to Level 3	0	0
Included in earnings	(600)	0
Included in other comprehensive income (loss)	412	0
Purchases and settlements (net)	0	0
Balance at end of period	2,400	2,588
Total gains and (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets still held at end of period	$ (412)	$ 0