Debt - Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Less – unamortized original issue discount	$ (26,464)	$ (4,738)
Less – unamortized original issue discount	(5,020)	(8,632)
Total debt, net of unamortized discounts	449,141	279,130
Current portion of long-term debt, net of unamortized discounts	(114,355)	(148,868)
Long-term debt, net of unamortized discounts	334,786	130,262
Credit Agreement | Term Loan
Debt Instrument [Line Items]
Total long-term debt, gross	140,625	142,500
Less - deferred financing costs	(4,424)	(4,738)
Total debt, net of unamortized discounts	136,201	137,762
Senior Convertible Notes 2016
Debt Instrument [Line Items]
Total long-term debt, gross	230,000
Less – unamortized original issue discount	(15,802)
Less - deferred financing costs	(6,238)
Total debt, net of unamortized discounts	207,960
Senior Subordinated Convertible Notes 2010
Debt Instrument [Line Items]
Total long-term debt, gross	110,000	150,000
Less – unamortized original issue discount	(4,609)	(7,923)
Less – deferred financing costs	(411)	(709)
Total debt, net of unamortized discounts	$ 104,980	$ 141,368