Income Taxes (Schedule of Reconciliation of Income Tax Rate to Effective Tax Rate) (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Provision at U.S. statutory rate	21.00%	28.10%	34.00%	34.00%
Net effect of taxes on foreign activities		8.40%	49.50%	(5.90%)
Tax effect of U.S. permanent differences		0.50%	14.70%	2.60%
State taxes and other, net		0.20%	4.90%	(1.50%)
Stock based compensation		1.30%	56.90%	0.00%
Other		(6.20%)	(1.30%)	3.80%
Valuation allowance		(15.10%)	(45.60%)	(172.90%)
Effective tax rate		17.20%	113.10%	(139.90%)