Consolidated Statement of Shareholders' Equity - 3 months ended Apr. 02, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance, Shares at Dec. 31, 2016	85,939,000	85,939,000
Beginning Balance at Dec. 31, 2016	$ 962,599	$ 172	$ 375,030	$ 643,825	$ (56,428)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under stock plans, shares		1,087,000
Stockholders' Equity, Period Increase (Decrease)		$ 2
Issuance of common stock under stock plans	29,139		29,137
Stock Repurchased During Period, Shares		380,000
Stock repurchased during period, Value	30,067	$ 1		30,066
Stock-based compensation expense	7,483		7,483
Payment of dividends	(6,497)			(6,497)
Net income	45,655			45,655
Net unrealized gain (loss) on cash flow hedges, net of tax of ($4)	(71)				(71)
Reclassification of net realized loss on cash flow hedges	44				44
Net unrealized gain (loss) on available-for-sale investments, net of tax of $92	511				511
Reclassification of net realized (gain) loss on the sale of available-for-sale investments	(65)				(65)
Foreign currency translation adjustment	$ 2,481				2,481
Ending Balance, Shares at Apr. 02, 2017	86,646,000	86,646,000
Ending Balance at Apr. 02, 2017	$ 1,011,212	$ 173	$ 411,650	$ 652,917	$ (53,528)