Income Taxes (Schedule Of A Reconciliation Of The Statutory Rate To The Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
INCOME TAXES [Abstract]
Federal statutory rate (as a percent)	21.00%	34.00%
State income taxes, net of federal benefit (as a percent)	0.70%	2.30%
U.S. Subpart F income (as a percent)	0.40%	1.60%
Global Intangible Low Tax Income (as a percent)	6.10%	0.00%
Share-based compensation (as a percent)	(3.50%)	(19.80%)
Research and experimentation (R&D) credit (as a percent)	(5.00%)	(13.90%)
Foreign rate difference (as a percent)	0.60%	13.60%
Changes to U.S. federal income tax law (as a percent)	0.00%	(93.80%)
Valuation allowance (as a percent)	(0.10%)	26.10%
Other, net (as a percent)	0.80%	5.40%
Effective tax rate (as a percent)	21.00%	(44.50%)
Effective Income Tax Rate Reconciliation Global Intangible Low Tax Income	6.10%	0.00%