Consolidated Statements Of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings (deficit)	Foreign currency translation adjustments	Available-for-sale investments-Change in net unrealized gains	Defined benefit pension adjustments
Balance (in shares) at Dec. 31, 2013		138,734
Balance at Dec. 31, 2013	$ 756,843	$ 1,387	$ 819,632	$ (88,599)	$ 25,280	$ 0	$ (857)
Shares issued under stock plans (in shares)		1,059
Shares issued under stock plans	1,080	$ 11	1,069	0	0	0	0
Share-based compensation expense	8,887	0	8,887	0	0	0	0
Tax benefit associated with stock plans	842	0	842	0	0	0	0
Pension liability adjustment	(150)	0	0	0	0	0	(150)
Reclassification adjustment associated with the sale of available-for-sale investments	0
Unrealized gain (loss) on available-for-sale investments	(1,884)
Foreign currency translation	(26,948)	0	0	0	(26,948)	0	0
Net income	7,887	$ 0	0	7,887	0	0	0
Balance (in shares) at Dec. 31, 2014		139,793
Balance at Dec. 31, 2014	748,441	$ 1,398	830,430	(80,712)	(1,668)	0	(1,007)
Shares issued under stock plans (in shares)		923
Shares issued under stock plans	1,756	$ 9	1,747	0	0	0	0
Share-based compensation expense	11,033	0	11,033	0	0	0	0
Tax benefit associated with stock plans	5,457	0	5,457	0	0	0	0
Pension liability adjustment	(142)	0	0	0	0	0	(142)
Reclassification adjustment associated with the sale of available-for-sale investments	0
Unrealized gain (loss) on available-for-sale investments	611	0	0	0	0	611	0
Foreign currency translation	(44,569)	0	0	0	(44,569)	0	0
Net income	80,296	$ 0	0	80,296	0	0	0
Balance (in shares) at Dec. 31, 2015		140,716
Balance at Dec. 31, 2015	802,883	$ 1,407	848,667	(416)	(46,237)	611	(1,149)
Shares issued under stock plans (in shares)		1,123
Shares issued under stock plans	826	$ 11	815	0	0	0	0
Share-based compensation expense	13,436	$ 0	13,436	0	0	0	0
Repurchase and retirement of common stock (in shares)		(519)
Repurchase and retirement of common stock	(7,573)	$ (5)	(3,140)	(4,428)
Pension liability adjustment	462	0	0	0	0	0	462
Reclassification adjustment associated with the sale of available-for-sale investments	(611)	0	0	0	0	(611)	0
Unrealized gain (loss) on available-for-sale investments	0
Foreign currency translation	(7,352)	0	0	0	(7,352)	0	0
Net income	97,147	$ 0	0	97,147	0	0	0
Balance (in shares) at Dec. 31, 2016		141,320
Balance at Dec. 31, 2016	$ 899,218	$ 1,413	$ 859,778	$ 92,303	$ (53,589)	$ 0	$ (687)