Debt, Summary of Debt, Net of Unamortized Deferred Loan Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Components of debt, net of unamortized deferred loan costs [Abstract]
Debt, net of unamortized discount	$ 146,410	$ 212,629
Less: deferred loan costs	(451)	(2,286)
Total debt	145,959	210,343
Less: current portion	(145,959)	(46,046)
Long-term debt	0	164,297
Cash Convertible Notes, Net of Unamortized Discount [Member]
Components of debt, net of unamortized deferred loan costs [Abstract]
Debt, net of unamortized discount	145,861	137,859
Capital Lease Obligations and Other [Member]
Components of debt, net of unamortized deferred loan costs [Abstract]
Debt, net of unamortized discount	549	1,270
Prior Credit Agreement [Member] | Term Loan [Member]
Components of debt, net of unamortized deferred loan costs [Abstract]
Debt, net of unamortized discount	0	60,000
Prior Credit Agreement [Member] | Revolver [Member]
Components of debt, net of unamortized deferred loan costs [Abstract]
Debt, net of unamortized discount	$ 0	$ 13,500