Consolidated Statements Of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Treasury Stock, Common	Additional paid-in capital	Retained earnings (deficit)	Foreign currency translation adjustments	Defined benefit pension adjustments
Balance	$ 993,018	$ 1,413	$ 0	$ 867,699	$ 147,418	$ (22,593)	$ (919)
Balance (in shares) at Dec. 31, 2017		141,283
Shares issued under stock plans (in shares)		1,120
Shares issued under stock plans	(9,109)	$ 11	0	(9,120)	0	0	0
Share-based compensation expense	17,112	$ 0	$ 0	17,112	0	0	0
Repurchase and retirement of common stock (in shares)		(6,224)	202
Repurchase and retirement of common stock	(179,315)	$ (62)	$ (7,112)	(38,066)	(134,075)
Dividends, Common Stock, Cash	(39,722)	0	0	33	(39,755)	0	0
Pension liability adjustment	59	0	0	0	0	0	59
Foreign currency translation	(10,183)	0	0	0	0	(10,183)	0
Cumulative effect of change in accounting principle	(590)	0	0	0	(590)	0	0
Net income	240,755	$ 0	$ 0	0	240,755	0	0
Balance (in shares) at Dec. 31, 2018		136,179	202
Balance	1,012,025	$ 1,362	$ (7,112)	837,658	213,753	(32,776)	(860)
Shares issued under stock plans (in shares)		877
Shares issued under stock plans	(1,431)	$ 9	0	(1,440)	0	0	0
Share-based compensation expense	19,629	$ 0	0	19,629	0	0	0
Repurchase and retirement of common stock (in shares)		(2,126)
Repurchase and retirement of common stock	(74,787)	$ (22)	0	(13,084)	(61,681)
Dividends, Common Stock, Cash	(40,784)	0	0	21	(40,805)	0	0
Pension liability adjustment	69	0	0	0	0	0	69
Foreign currency translation	(3,692)	0	0	0	0	(3,692)	0
Net income	254,860	$ 0	$ 0	0	254,860	0	0
Balance (in shares) at Dec. 31, 2019		134,930	202
Balance	1,165,889	$ 1,349	$ (7,112)	842,784	366,127	(36,468)	(791)
Shares issued under stock plans (in shares)		997
Shares issued under stock plans	(16,062)	$ 10	0	(16,072)	0	0	0
Share-based compensation expense	22,920	$ 0	0	22,920	0	0	0
Repurchase and retirement of common stock (in shares)		(778)
Repurchase and retirement of common stock	(44,563)	$ (8)	0	(4,820)	(39,735)	0
Dividends, Common Stock, Cash	(43,490)	0	0	38	(43,528)	0	0
Pension liability adjustment	(49)	0	0	0	0	0	(49)
Foreign currency translation	(120)	0	0	0	0	(120)	0
Net income	294,969	$ 0	$ 0	0	294,969	0	0
Balance (in shares) at Dec. 31, 2020		135,149	202
Balance	$ 1,379,494	$ 1,351	$ (7,112)	$ 844,850	$ 577,833	$ (36,588)	$ (840)