Pensions and Other Postretirement Benefits Fair Value Measurement (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 10,156	$ 8,802
Liabilities, Fair Value Disclosure	15,203	13,063
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	2,932	2,275
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	10,156	8,802
Liabilities, Fair Value Disclosure	12,271	10,788
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	$ 0	$ 0