Fair Value Measurements - Summary of Short-Term and Long-Term Investments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 29, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 416,676	$ 353,109
Gross Unrealized Gains	755	582
Gross Unrealized Losses	(700)	(723)
Estimated Fair Value	416,731	352,968
Obligations of Government-Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	30,141	33,506
Gross Unrealized Gains	5	5
Gross Unrealized Losses	0	(1)
Estimated Fair Value	30,146	33,510
State and Municipal Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	56,671	51,573
Gross Unrealized Gains	74	82
Gross Unrealized Losses	(35)	(28)
Estimated Fair Value	56,710	51,627
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	192,404	166,642
Gross Unrealized Gains	622	453
Gross Unrealized Losses	(588)	(675)
Estimated Fair Value	192,438	166,420
Other Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	22,849	11,771
Gross Unrealized Gains	16	15
Gross Unrealized Losses	(26)	(1)
Estimated Fair Value	22,839	11,785
U.S. Government and Agency Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	114,611	89,617
Gross Unrealized Gains	38	27
Gross Unrealized Losses	(51)	(18)
Estimated Fair Value	$ 114,598	$ 89,626