Fair Value Measurements - Maturity Dates of Investments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 28, 2014	Dec. 31, 2013
Fair Value Measurements, Maturity Dates Of Investments [Line Items]
Amortized Cost	$ 457,698	$ 353,109
Estimated Fair Value	458,232	352,968
Less Than 1 Year [Member]
Fair Value Measurements, Maturity Dates Of Investments [Line Items]
Amortized Cost	108,570
Estimated Fair Value	108,664
1 to 5 Years [Member]
Fair Value Measurements, Maturity Dates Of Investments [Line Items]
Amortized Cost	346,128
Estimated Fair Value	346,980
6 to 10 Years [Member]
Fair Value Measurements, Maturity Dates Of Investments [Line Items]
Amortized Cost	3,000
Estimated Fair Value	2,588
Thereafter [Member]
Fair Value Measurements, Maturity Dates Of Investments [Line Items]
Amortized Cost	0
Estimated Fair Value	$ 0