Cash, Cash Equivalents, and Investments - Components of Cash, Cash Equivalents, and Investments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cash	$ 36,740	$ 40,124
Money market instruments	5,723	520
Cash and cash equivalents	42,463	40,644	42,757	45,160
Short-term investments	41,777	184,822
Limited partnership interest	1,956	1,956
Long-term investments	379,916	229,655
Total	464,156	455,121
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	33,585	109,040
Long-term investments	190,767	109,909
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
Long-term investments	86,804	73,666
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	4,766	9,276
Long-term investments	7,013	5,919
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	410	53,559
Long-term investments	74,475	21,820
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	3,016	11,448
Long-term investments	17,401	16,385
Agency Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	0	1,499
Long-term investments	$ 1,500	$ 0