Borrowing Arrangements (Details) In Thousands, unless otherwise specified					12 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2012 EUR (€)	Dec. 31, 2012 GBP (£)	Dec. 31, 2011 USD ($)	Dec. 31, 2012 Letter of Credit [Member] USD ($)	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Taxable Industrial Revenue Bond [Member] USD ($)	Dec. 31, 2012 Tax Exempt Industrial Revenue Bond One [Member] USD ($)	Dec. 31, 2012 Tax Exempt Industrial Revenue Bond Two [Member] USD ($)
Line of Credit Facility [Line Items]
Tax-exempt IRB maturing in 2027/2020/2029							$ 7,116	$ 4,120	$ 2,075
Interest at a floating rate on tax-exempt IRB maturing in 2029/2020/2027							0.22%	0.22%	0.25%
Expiry date of Credit facility					Aug. 01, 2014
Period for renewing the Facility						1 year
Available letter of Credit facility					13,566
Borrowing Arrangements (Textual) [Abstract]
Short-term lines of credit maintained	9,400	400	3,000
Outstanding lines of credit	$ 0			$ 0