Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Assets:
Pensions	$ 15,148	$ 14,442
Deferred revenue	718	139
Other accruals and reserves	10,979	11,735
Inventories	496	217
Legal and environmental accruals	6,463	6,679
Deferred compensation	17,461	14,347
Bad debt and rebate reserve	2,884	3,353
Subsidiaries net operating loss carryforwards	1,390	1,991
Tax credit carryforwards	532	31
Deferred Tax Assets, Gross, Total	56,071	52,934
Deferred Tax Liabilities:
Depreciation	(50,011)	(47,218)
Amortization of intangibles	(456)	(829)
Unrealized foreign exchange loss	(602)	(1,049)
Other	(918)	(640)
Deferred Tax Liabilities, Gross, Total	(51,987)	(49,736)
Valuation Allowance	(603)	(742)
Net Deferred Tax Assets	3,481	2,456
Reconciliation to Consolidated Balance Sheet:
Current deferred tax assets	9,876	8,769
Non-current deferred tax assets (in other non-current assets)	2,805	2,331
Non-current deferred tax liabilities	(9,200)	(8,644)
Net Deferred Tax Assets	$ 3,481	$ 2,456