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	$ 899,218	$ 1,413	$ 0	$ 859,778	$ 92,303	$ (53,589)	$ (687)
Balance (in shares) at Dec. 31, 2016		141,320
Shares issued under stock plans (in shares)		1,040
Shares issued under stock plans	(321)	$ 11	0	(332)	0	0	0
Share-based compensation expense	15,306	$ 0	0	15,306	0	0	0
Repurchase and retirement of common stock (in shares)		(1,077)
Repurchase and retirement of common stock	(28,000)	$ (11)	0	(6,565)	(21,424)
Dividends, Common Stock, Cash	(9,896)	0	0	0	(9,896)	0	0
Pension liability adjustment	(232)	0	0	0	0	0	(232)
Foreign currency translation	29,294	0	0	0	0	29,294	0
Reclassification of cumulative translation adjustment associated with liquidated and planned sale of subsidiaries	1,702	0	0	0	0	1,702	0
Net income	85,066	$ 0	0	0	85,066	0	0
Balance (in shares) at Dec. 31, 2017		141,283
Balance	993,018	$ 1,413	0	867,699	147,418	(22,593)	(919)
Cumulative Effect of New Accounting Principle in Period of Adoption	881	$ 0	0	(488)	1,369	0	0
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
Reclassification of cumulative translation adjustment associated with liquidated and planned sale of subsidiaries	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)
Cumulative Effect of New Accounting Principle in Period of Adoption	(590)	$ 0	0	0	(590)	0	0
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)	0
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
Reclassification of cumulative translation adjustment associated with liquidated and planned sale of subsidiaries	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)