Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income, Net	Accumulated Earnings	Treasury Stock
Beginning Balance at Dec. 31, 2016	$ 60,878	$ 78	$ 863,127	$ (49,683)	$ 1,644,005	$ (2,396,649)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,279				3,279
Other comprehensive income (loss)	51,191			51,191
Issuances under stock plans and for an acquisition	830,446	4	819,313			11,129
Common share repurchases	(41,272)					(41,272)
Stock-based compensation expense	78,943		78,943
Ending Balance at Dec. 31, 2017	983,465	82	1,761,383	1,508	1,647,284	(2,426,792)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU No. 2018-02	0			591	(591)
Net income	122,456				122,456
Other comprehensive income (loss)	(41,966)			(41,966)
Issuances under stock plans	10,181		(3,845)			14,026
Common share repurchases	(275,834)					(275,834)
Stock-based compensation expense	66,172		66,172
Ending Balance at Dec. 31, 2018	850,757	82	1,823,710	(39,867)	1,755,432	(2,688,600)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	233,290				233,290
Other comprehensive income (loss)	(38,071)			(38,071)
Issuances under stock plans	17,649		6,555			11,094
Common share repurchases	(194,040)					(194,040)
Stock-based compensation expense	69,008		69,008
Ending Balance at Dec. 31, 2019	$ 938,593	$ 82	$ 1,899,273	$ (77,938)	$ 1,988,722	$ (2,871,546)