Debt (Future Debt Maturities of Long-term Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Remaining 2018	$ 2,063
2019	6,188
2020	8,250
2021	8,250
2022	137,186
Thereafter	0
Long-term debt	161,937
Less current maturities	(3,290)	$ (2,301)
Less unamortized debt discount	(2,890)	$ (2,700)
Notes Payable, less current maturities and unamortized debt discount	$ 155,757