Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes [Textual] [Abstract]
Effective Income Tax Rate Reconciliation, Percent	(15.90%)	(13.10%)	(11.60%)	(9.30%)
Reserve for Uncertain Tax Positions	$ 1,316		$ 1,316		$ 1,570
Income Tax Examination, Penalties and Interest Expense	18		61
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	135
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 173		$ 173