Income Taxes (Schedule of Reasons Attributable to the Differences Between Effective Income Tax Rate And Federal Statutory Rate) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	35.00%	35.00%	35.00%
Increase (decrease) resulting from:
Foreign rate differences	(12.20%)	(12.60%)	(12.30%)
Dividend repatriation cost	16.40%	5.80%	5.70%
Other	1.50%	(0.30%)	(0.40%)
Effective tax rate	40.70%	27.90%	28.00%