Cash, Cash Equivalents, and Investments - Components of Cash, Cash Equivalents, and Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cash	$ 30,221	$ 34,986
Cash equivalents		5,098
Money market instruments	225	5,076
Cash and cash equivalents	30,446	45,160	54,158	38,103
Short-term investments	186,572	105,105
Limited partnership interest (accounted for using cost method)	2,455	3,740
Long-term investments	226,720	238,255
Total	443,738	388,520
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	104,720	46,001
Long-term investments	105,621	100,072
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	41,269	17,666
Long-term investments	28,659	34,710
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	17,013	16,224
Long-term investments	10,992	17,846
Treasury Bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	11,654	5,997
Long-term investments	57,623	36,276
Sovereign Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	8,553	3,986
Long-term investments	21,370	10,606
Corporate Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	1,864	2,131
Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	1,499	7,482
Long-term investments		29,441
Covered Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments		5,618
Long-term investments		$ 5,564