Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 25,915	$ 33,588
Effective tax rate	21.00%	31.00%
State and local income tax expense	$ 3,400	$ 3,000
Tax expense relating stock compensation	2,500	4,600
Tax expense (benefit) relating to uncertain tax positions	1,400	2,800
Tax expense from foreign operations	1,300	$ 4,000
Tax benefit from foreign operations	5,400
Federal statutory rate		21.00%
Tax expense (benefit) from change in valuation allowance		$ 2,700
Foreign tax credit carry forwards	32,400
Valuation allowance	32,400
Second component of tax deductible goodwill, net of tax	$ 300