Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 124,800	$ 324,000	$ 335,300
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	124,900	323,900	335,300
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	24,200	(2,800)	(18,100)
Unrealized (loss) gain on derivative instruments	(9,400)	(6,500)	400
Retirement plan and other activity	(500)	200	300
Comprehensive income	139,100	314,900	317,900
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	139,200	314,800	317,900
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	$ (100)	$ 100	$ 0