Debt (Details Textual)	1 Months Ended					1 Months Ended		1 Months Ended	12 Months Ended
	Jul. 31, 2013 financial_institution	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 Line of Credit [Member]	Dec. 31, 2013 Line of Credit [Member]	Apr. 30, 2011 Toledo-Lucas County Port Authority and Dayton-Montgomery County Port Authority [Member] USD ($)	Dec. 31, 2014 Toledo-Lucas County Port Authority and Dayton-Montgomery County Port Authority [Member] USD ($)	Nov. 30, 1996 Lorain Port Authority [Member] USD ($)	Dec. 31, 2014 Lorain Port Authority [Member]	Dec. 31, 2013 Lorain Port Authority [Member]	Dec. 31, 2014 Revolving Credit Facility [Member] USD ($)	Jul. 31, 2013 Revolving Credit Facility [Member] USD ($)	Dec. 31, 2014 Letter of Credit [Member] USD ($)	Dec. 31, 2014 Foreign Line of Credit [Member] EUR (€)
Line of Credit Facility [Line Items]
Line of Credit Facility, Number of Financial Institutions	6
Maximum borrowing amount under revolving credit agreement											$ 375,000,000	$ 375,000,000
Additional term loan												100,000,000
Outstanding amount													42,500,000
Variable commitment fee											0.225%
Amount of maximum available unused credit		334,800,000
Aggregate available borrowings		229,400,000
Foreign lines of credit committed and secured														3,500,000
Average interest rate on short term debt				4.90%	2.47%
Amount issued in variable rate industrial revenue bonds						8,000,000		8,300,000
Interest rate on bonds							4.90%
Unamortized balance of the bonds		$ 5,961,000	$ 6,575,000				$ 6,000,000
Variable rate minimum									0.18%	0.19%
Variable rate maximum									0.28%	0.38%