Basis of Presentation and Significant Accounting Policies (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowances for Doubtful Accounts [Table]
At beginning of period	$ 1,849,000	$ 2,590,000	$ 5,007,000
Activity in the period:
Provision for doubtful accounts	(237,000)	973,000	(1,000)
Account chargeoffs	(527,000)	(1,714,000)	(2,416,000)
At end of period	1,085,000	1,849,000	2,590,000
Inventories Detail [Table]
Finished goods	72,312,000	71,247,000
Raw materials	5,396,000	5,653,000
Parts and supplies	24,497,000	22,216,000
Work in progress	836,000	869,000
Inventories	103,041,000	99,985,000
Depreciation and depletion expense	70,700,000	87,700,000	139,700,000
Interest capitalized	2,000,000	1,200,000	1,100,000
Amortization expense of patents, trademarks, and other intangible assets	4,500,000	2,800,000	2,800,000
Future amortization expense, 2013	4,800,000
Future amortization expense, 2014	3,500,000
Future amortization expense, 2015	3,400,000
Future amortization expense, 2016	3,200,000
Future amortization expense, 2017	$ 3,000,000
Buildings [Member] | Minimum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	15 years
Buildings [Member] | Maximum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	40 years
Barges and vessels [Member] | Minimum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	5 years
Barges and vessels [Member] | Maximum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	30 years
Machinery and equipment [Member] | Minimum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	2 years
Machinery and equipment [Member] | Maximum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	20 years
Automobiles and trucks [Member] | Maximum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	4 years
Chemical plants [Member] | Minimum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	15 years
Chemical plants [Member] | Maximum [Member]
Property, Plant, and Equipment [Line Items]
Estimated useful lives	30 years