Cash, Cash Equivalents, and Investments - Components of Cash, Cash Equivalents, and Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 28, 2014	Dec. 31, 2013	Sep. 29, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cash	$ 37,611	$ 40,124
Money market instruments	568	520
Cash and cash equivalents	38,179	40,644	30,446	45,160
Short-term investments	49,758	184,822
Limited partnership interest	1,956	1,956
Long-term investments	409,283	229,655
Total	497,220	455,121
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	45,889	109,040
Long-term investments	209,379	109,909
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	1,971	9,276
Long-term investments	7,043	5,919
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	1,709	11,448
Long-term investments	17,525	16,385
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	189	53,559
Long-term investments	64,941	21,820
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
Long-term investments	102,674	73,666
Agency Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	0	1,499
Long-term investments	$ 5,765	$ 0