Condensed Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income		$ 75,665	$ 72,410
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments		(2,984)	611
Post retirement plans, amortization of actuarial loss included in net income (1)	[1]	550	535
Other comprehensive (loss) income		(2,434)	1,146
Comprehensive income		$ 73,231	$ 73,556

[1] Net of tax of $0.1 million for each of the three months ended March 31, 2020 and 2019.