Long-Term Debt (Senior Credit Facility) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Senior Credit Facility [Member]	Jul. 08, 2011 Senior Credit Facility [Member]	Dec. 31, 2011 Maximum [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Minimum [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Alternative A [Member] Maximum [Member] Libor [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Alternative A [Member] Minimum [Member] Libor [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Alternative B [Member] Federal Funds [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Alternative B [Member] Monthly Libor [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Alternative B [Member] Maximum [Member] Libor [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Alternative B [Member] Minimum [Member] Libor [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Standby Letters Of Credit Guaranteeing Company Industrial Revenue Bonds [Member] Industrial Revenue Bonds [Member] Senior Credit Facility [Member]	Dec. 31, 2011 Standby Letters Of Credit Related To Various Insurance Contracts And Foreign Vendor Commitments [Member] Senior Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, maturity date			July 8, 2016
Utilized borrowings under credit facility			$ 298,000
Maximum borrowing capacity under credit facility			900,000	900,000
Basis spread on debt instrument							2.00%	1.25%	0.50%	1.00%	1.00%	0.25%
Commitment fee percentage					0.40%	0.25%
Consolidated interest coverage ratio					3.0	1.0
Consolidated net leverage ratio					3.75	1.00
Amount utilized from long-term lines of credit			395,336
Standby letters of credit for various insurance contracts and commitments to foreign vendors	50,540	53,549											46,796	50,540
Available amount under credit facility			$ 504,664