Financing Arrangements and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt, gross	$ 185,968	$ 183,636
Unamortized discount and debt issuance costs	(24,982)	(27,368)
Long-term debt	160,986	156,268
Long-term debt, current maturities, gross	(85,968)	(83,636)
Unamortized discount and debt issuance costs, current	89	268
Long-term debt, current maturities	(85,879)	(83,368)
Long-term debt, excluding current maturities, gross	100,000	100,000
Unamortized discount and debt issuance costs, noncurrent	(24,893)	(27,100)
Long-term debt, excluding current maturities	75,107	72,900
Other Debt
Debt Instrument [Line Items]
Long-term debt, gross	2,712	380
Long-term debt	2,712	380
Senior notes | Convertible Notes due 2017
Debt Instrument [Line Items]
Long-term debt, gross	83,256	83,256
Unamortized discount and debt issuance costs	(89)	(268)
Long-term debt	83,167	82,988
Senior notes | Convertible Notes due 2021
Debt Instrument [Line Items]
Long-term debt, gross	100,000	100,000
Unamortized discount and debt issuance costs	(24,893)	(27,100)
Long-term debt	75,107	72,900
Revolving credit facility | ABL Facility
Debt Instrument [Line Items]
Long-term debt, gross	0	0
Long-term debt	$ 0	$ 0