Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Accrued Liabilities [Abstract]
Payroll and other compensation	$ 41,070	$ 38,530
Pension and other postretirement benefits	8,405	8,401
Other	42,775	39,671
Accrued liabilities	$ 92,250	$ 86,602