Consolidated Statement of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2014	$ 736,437	$ 173	$ 251,717	$ 523,946	$ (39,399)
Beginning Balance, Shares at Dec. 31, 2014	86,542	86,542
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under stock option plans, shares		586
Issuance of common stock under stock option plans	9,666	1	9,665
Stock-based compensation expense	6,946		6,946
Excess tax benefit from stock option exercises	3,694		3,694
Tax benefit for research and development credits as a result of stock options	48		48
Net income	20,502			20,502
Net unrealized loss on cash flow hedges, net of tax of $73	(520)				(520)
Reclassification of net realized (gain) loss into current operations	110				110
Net unrealized gain on available-for-sale investments, net of tax of $134	899				899
Reclassification of net realized gain on the sale of available-for-sale investments	(29)				(29)
Foreign currency translation adjustment, net of tax of $636	(10,690)				(10,690)
Ending Balance at Apr. 05, 2015	$ 767,063	$ 174	$ 272,070	$ 544,448	$ (49,629)
Ending Balance, Shares at Apr. 05, 2015	87,128	87,128