Income Taxes (Reconciliation Of The Statutory Federal Income Tax Rate To The Effective Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Percent [Abstract]
State income taxes (net of federal income tax benefit)	0.80%	0.60%	0.70%
Foreign income taxed at lower rate than U.S. statutory rate	(11.60%)	(10.20%)	(17.10%)
Resolution and expiration of statutes of limitation of uncertain tax positions	(6.50%)	(3.10%)	(0.70%)
Permanent foreign exchange losses	(0.60%)	(8.20%)	(4.60%)
Research credits, uncertain tax positions and other	(1.00%)	3.40%	1.10%
Revaluation of U.S. deferred income taxes	(41.50%)	0.00%	0.00%
TCJA - Transition Tax	41.40%	0.00%	0.00%
Effective income tax rate	16.00%	17.50%	14.40%