Selected quarterly financial results (unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Apr. 19, 2011	Apr. 14, 2011
Selected Quarterly Financial Information [Abstract]
Debt Instrument, Face Amount													$ 2,200,000,000
Revenue, Net	296,162,000	304,507,000	305,094,000	308,743,000	294,093,000	299,567,000	293,004,000	302,619,000	1,214,506,000	1,189,282,000	1,215,445,000
Operating Income (Loss)	44,128,000	61,137,000	59,371,000	62,613,000	44,612,000	48,713,000	(5,998,000)	52,751,000	227,249,000	140,078,000	103,524,000
Income (Loss) from Continuing Operations, before Income Taxes	17,558,000	32,214,000	(53,238,000)	38,014,000	20,866,000	21,718,000	(40,667,000)	18,844,000	34,546,000	20,760,000	(6,169,000)
Net income (loss)	7,379,000	18,884,000	(41,313,000)	21,846,000	10,921,000	11,924,000	(24,892,000)	10,678,000	6,794,000	8,630,000	(4,667,000)
Earnings Per Share, Basic	$ 0.23	$ 0.58	$ (1.10)	$ 0.37	$ 0.19	$ 0.20	$ (0.43)	$ 0.18	$ 0.17	$ 0.15	$ (0.08)
Earnings Per Share, Diluted	$ 0.22	$ 0.56	$ (1.10)	$ 0.37	$ 0.18	$ 0.20	$ (0.43)	$ 0.18	$ 0.17	$ 0.15	$ (0.08)
Stock Repurchase from the Estate of Craig H. Neilsen, Shares												26,150,000
Stock Repurchase From Estate, Outstanding Share Percentage												45.00%
Repurchase Transaction, Earnings Per Share Impact									$ 0.54
Goodwill and Intangible Asset Impairment							$ 56,000,000
East Chicago Impairment, Earnings Per Share Impact							$ 0.56