Financing Arrangements and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt, gross	$ 248,619	$ 183,636
Unamortized discount and debt issuance costs	(23,779)	(27,368)
Long-term debt	224,840	156,268
Long-term debt, current maturities, gross	(85,119)	(83,636)
Unamortized discount and debt issuance costs, current	0	268
Long-term debt, current maturities	(85,119)	(83,368)
Long-term debt, excluding current maturities, gross	163,500	100,000
Unamortized discount and debt issuance costs, noncurrent	(23,779)	(27,100)
Long-term debt, excluding current maturities	139,721	72,900
Other Debt
Debt Instrument [Line Items]
Long-term debt, gross	1,867	380
Long-term debt	1,867	380
Senior notes | Convertible Notes due 2017
Debt Instrument [Line Items]
Long-term debt, gross	83,252	83,256
Unamortized discount and debt issuance costs	0	(268)
Long-term debt	83,252	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	(23,779)	(27,100)
Long-term debt	76,221	72,900
Revolving credit facility | ABL Facility
Debt Instrument [Line Items]
Long-term debt, gross	63,500	0
Long-term debt	$ 63,500	$ 0