Domestic And Foreign Income Taxes (Schedule Of Reconciliation Of The Statutory Federal Income Tax Rate To The Effective Tax Rate Based On Income (Loss)) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Domestic And Foreign Income Taxes [Abstract]
Tax provision at statutory rate	34.00%	34.00%	34.00%
Change in valuation allowance	(502.26%)	(46.42%)	(20.08%)
Impact of permanent items, including stock based compensation expense	19.62%	(7.93%)	(21.33%)
Effect of foreign tax rates	7.04%	2.49%	7.82%
State taxes net of federal benefit	8.03%	5.05%	1.92%
Effect of dividend of foreign subsidiary in prior year	74.41%	(3.85%)	5.18%
Prior year provision to return true-up	48.21%	10.60%	(6.70%)
Non-controlling interest	2.08%	(1.77%)	1.22%
Change in expected future rate	331.39%
Other	(21.83%)	(0.03%)	(1.40%)
Domestic and foreign income tax rate	0.69%	(7.86%)	0.63%