Commitments (Future Minimum Purchase Requirements) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Recorded Unconditional Purchase Obligation [Line Items]
Future minimum purchase requirements, 2012	$ 43,632
Future minimum purchase requirements, 2013	30,624
Future minimum purchase requirements, 2014	23,112
Future minimum purchase requirements, 2015	5,205
Future minimum purchase requirements, 2016
Future minimum purchase requirements, Thereafter
Raw And Other Materials [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Future minimum purchase requirements, 2012	39,660
Future minimum purchase requirements, 2013	27,964
Future minimum purchase requirements, 2014	20,715
Future minimum purchase requirements, 2015	2,808
Future minimum purchase requirements, 2016
Future minimum purchase requirements, Thereafter
Transportation [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Future minimum purchase requirements, 2012	1,575
Future minimum purchase requirements, 2013	263
Future minimum purchase requirements, 2014
Future minimum purchase requirements, 2015
Future minimum purchase requirements, 2016
Future minimum purchase requirements, Thereafter
Information Systems And Services [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Future minimum purchase requirements, 2012	2,397
Future minimum purchase requirements, 2013	2,397
Future minimum purchase requirements, 2014	2,397
Future minimum purchase requirements, 2015	2,397
Future minimum purchase requirements, 2016
Future minimum purchase requirements, Thereafter