Income Taxes (Schedule of Components of Income before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ 435,900	$ 452,200	$ 341,100
Foreign	(10,700)	58,700	24,200
Income before income taxes	$ 425,164	$ 510,939	$ 365,303