Convertible Debentures and Credit Arrangements	3 Months Ended
Mar. 31, 2017
Debt Disclosure [Abstract]
Convertible Debentures and Credit Arrangements	Convertible Debentures In November 2012, the Company issued $55.0 million principal amount of its 5.25% convertible senior debentures due on May 15, 2018 (the "2018 Debentures"). The 2018 Debentures may be settled in cash or partially in cash upon conversion. Accordingly, the Company separately accounts for the liability and equity components of the 2018 Debentures. The carrying amount of the liability component was determined at the transaction date by measuring the fair value of a similar liability that does not have an associated equity component. The carrying amount of the equity component represented by the embedded conversion option was determined by deducting the fair value of the liability component from the initial proceeds of the 2018 Debentures as a whole. At March 31, 2017, the fair value of the $55.0 million outstanding 2018 Debentures was approximately $56.1 million, based on the midpoint of the bid and ask prices as of such date. At March 31, 2017, the carrying amount of the equity component was $6.4 million, the principal amount of the liability component was $55.0 million, the unamortized discount was $1.6 million, unamortized debt issuance costs were $0.4 million and the net carrying value of the liability component was $53.0 million. The Company is amortizing the excess of the face value of the 2018 Debentures over their carrying value over their term as additional interest expense using the effective interest method and recorded $0.4 million and $0.3 million of such expense for the three months ended March 31, 2017 and 2016, respectively. The effective interest rate on the 2018 Debentures is 8.7%. The Company anticipates refinancing all or a portion of the outstanding 2018 Debentures before the maturity date of May 15, 2018.

Convertible Debentures

In November 2012, the Company issued $55.0 million principal amount of its 5.25% convertible senior debentures due on May 15, 2018 (the "2018 Debentures"). The 2018 Debentures may be settled in cash or partially in cash upon conversion. Accordingly, the Company separately accounts for the liability and equity components of the 2018 Debentures. The carrying amount of the liability component was determined at the transaction date by measuring the fair value of a similar liability that does not have an associated equity component. The carrying amount of the equity component represented by the embedded conversion option was determined by deducting the fair value of the liability component from the initial proceeds of the 2018 Debentures as a whole. At March 31, 2017, the fair value of the $55.0 million outstanding 2018 Debentures was approximately $56.1 million, based on the midpoint of the bid and ask prices as of such date. At March 31, 2017, the carrying amount of the equity component was $6.4 million, the principal amount of the liability component was $55.0 million, the unamortized discount was $1.6 million, unamortized debt issuance costs were $0.4 million and the net carrying value of the liability component was $53.0 million. The Company is amortizing the excess of the face value of the 2018 Debentures over their carrying value over their term as additional interest expense using the effective interest method and recorded $0.4 million and $0.3 million of such expense for the three months ended March 31, 2017 and 2016, respectively. The effective interest rate on the 2018 Debentures is 8.7%. The Company anticipates refinancing all or a portion of the outstanding 2018 Debentures before the maturity date of May 15, 2018.