Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock Issued [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]	Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Noncontrolling Interest in Variable Interest Entity	$ 0
Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,578,734
Common Stock, Value, Issued at Dec. 31, 2015		$ 27,709
Additional Paid in Capital at Dec. 31, 2015			$ 230,179
Treasury Stock, Carrying Basis at Dec. 31, 2015				$ (743,577)
Retained Earnings at Dec. 31, 2015					$ 2,364,786
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax at Dec. 31, 2015						$ (297,515)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax at Dec. 31, 2015							$ (2,848)
Balance at Dec. 31, 2015	1,578,734
Stockholders' Equity [Roll Forward]
Net Income	24,586				24,586
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(5,559)					(5,559)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	3,258						(3,258)
Other Comprehensive Income	(2,301)
Restricted stock unit activity	12,766		2,338	10,428
Restricted stock activity	0		(1,947)	1,947
Tax benefits from stock plans	(3,004)		(3,004)
Cash dividends	(94,138)				(94,138)
Common Stock, Value, Issued at Dec. 31, 2016		27,709
Additional Paid in Capital at Dec. 31, 2016			227,566
Treasury Stock, Carrying Basis at Dec. 31, 2016				(731,202)
Retained Earnings at Dec. 31, 2016					2,295,234
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax at Dec. 31, 2016						(303,074)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax at Dec. 31, 2016							410
Balance at Dec. 31, 2016	1,516,643
Noncontrolling Interest in Variable Interest Entity	0
Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,516,643
Net Income	166,398				166,398
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	10,723					10,723
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(195)						195
Other Comprehensive Income	10,528
Restricted stock unit activity	9,815		480	9,335
Restricted stock activity	0		(2,921)	2,921
Cash dividends	(44,220)				(44,220)
Common Stock, Value, Issued at Dec. 31, 2017	27,709	27,709
Additional Paid in Capital at Dec. 31, 2017			225,125
Treasury Stock, Carrying Basis at Dec. 31, 2017				(718,946)
Retained Earnings at Dec. 31, 2017	2,417,412				2,417,412
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax at Dec. 31, 2017						(292,351)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax at Dec. 31, 2017							215
Balance at Dec. 31, 2017	1,659,164
Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Increase from Business Combination	5,354
Noncontrolling Interest in Variable Interest Entity	5,354
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,664,518
Net Income	(212,327)				(212,327)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(47,026)					(47,026)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(215)						(215)
Other Comprehensive Income	(47,241)
Restricted stock unit activity	10,176		(753)	10,929
Restricted stock activity	0		(3,951)	3,951
Cash dividends	0
Common Stock, Value, Issued at Dec. 31, 2018	27,709	$ 27,709
Additional Paid in Capital at Dec. 31, 2018			$ 220,421
Treasury Stock, Carrying Basis at Dec. 31, 2018				$ (704,066)
Retained Earnings at Dec. 31, 2018	2,204,548				$ 2,204,548
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax at Dec. 31, 2018						$ (339,377)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax at Dec. 31, 2018							$ 0
Balance at Dec. 31, 2018	1,409,235
Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Period Increase (Decrease)	709
Noncontrolling Interest, Increase from Business Combination	709
Noncontrolling Interest in Variable Interest Entity	6,063
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,415,298
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (537)