Restructuring And Impairment Costs (Cumulative Restructuring And Impairment Costs) (Details) (USD $) In Thousands	3 Months Ended					6 Months Ended				12 Months Ended	18 Months Ended
	Sep. 30, 2011		Dec. 31, 2010	Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Mar. 31, 2011	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Employee termination benefits											$ 17,879
Pension curtailment and settlement costs										4,100	4,081
Other costs											3,733
Total restructuring cost											25,693
Impairment costs - Property, plant and equipment			5,600								5,632
Total restructuring and impairment costs	2,962	[1]		2,020	[1]	9,821	[1]	2,969	[1]		31,325
Closure Of Processing Facility In Canada [Member]
Restructuring Cost and Reserve [Line Items]
Employee termination benefits											2,412
Pension curtailment and settlement costs											4,081
Other costs
Total restructuring cost											6,493
Impairment costs - Property, plant and equipment											5,632
Total restructuring and impairment costs											12,125
Other Restructuring And Cost Reduction Initiatives [Member]
Restructuring Cost and Reserve [Line Items]
Employee termination benefits											15,467
Pension curtailment and settlement costs
Other costs											3,733
Total restructuring cost											19,200
Impairment costs - Property, plant and equipment
Total restructuring and impairment costs											$ 19,200

[1] Item is not included in segment operating income, but is included in consolidated operating income.