Basis of Presentation and Significant Accounting Policies (Details) (USD $)	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Inventories Detail [Table]
Finished goods	$ 64,756,000			$ 64,756,000		$ 72,312,000
Raw materials	4,269,000			4,269,000		5,396,000
Parts and supplies	22,576,000			22,576,000		24,497,000
Work in progress	724,000			724,000		836,000
Inventories	92,325,000			92,325,000		103,041,000
Weighted Average Shares Outstanding [Table]
Number of weighted average common shares outstanding	78,030,000	77,329,000		77,867,000	77,226,000
Assumed exercise of stock options	933,000	1,609,000		852,000	1,514,000
Average diluted shares outstanding	78,963,000	78,938,000		78,719,000	78,740,000
Average market price of common stock for the period				$ 10.07
Outstanding stock options excluded from average diluted shares outstanding	1,571,777	2,144,779		2,241,490	2,054,303
Proceeds from insurance settlements				7,600,000
Fair value of Senior Notes	323,200,000			323,200,000		327,400,000
Carrying value of Senior Notes	305,000,000			305,000,000		305,000,000
Fair value of contingent purchase price consideration	600,000			600,000		2,700,000
Prior period reclassification adjustment		$ 400,000	$ 700,000		$ 1,200,000