Other Long Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Long Term Liabilities [Line Items]
Derivative liability	$ 0	$ 1,964
Other Noncurrent Liabilities
Other Long Term Liabilities [Line Items]
Derivative liability		2,000
Unrecognized tax benefit liabilities and long term notes payables	$ 13,000	$ 14,400