FAIR VALUE OF FINANCIAL INSTRUMENTS (Debt) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 588,113	$ 586,430
Estimate Of Fair Value Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	616,668	626,110
Estimate Of Fair Value Fair Value Disclosure [Member] | Industrial Revenue Bond [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	8,808	9,004
Estimate Of Fair Value Fair Value Disclosure [Member] | Senior Notes Five Seventy Four [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	129,568	134,982
Estimate Of Fair Value Fair Value Disclosure [Member] | Senior Notes Five Fifty One [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	174,001	172,871
Estimate Of Fair Value Fair Value Disclosure [Member] | Senior Notes Three Eighty Four [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	100,789	101,886
Estimate Of Fair Value Fair Value Disclosure [Member] | Senior Notes Four Twenty Four [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	200,982	204,965
Estimate Of Fair Value Fair Value Disclosure [Member] | Other Debt Obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long Term Debt Fair Value	2,520	2,402
Carrying Reported Amount Fair Value Disclosure [Member] | Industrial Revenue Bond [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	8,808	9,004
Carrying Reported Amount Fair Value Disclosure [Member] | Senior Notes Five Seventy Four [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	125,014	125,024
Carrying Reported Amount Fair Value Disclosure [Member] | Senior Notes Five Fifty One [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	150,000	150,000
Carrying Reported Amount Fair Value Disclosure [Member] | Senior Notes Three Eighty Four [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	100,789	100,000
Carrying Reported Amount Fair Value Disclosure [Member] | Senior Notes Four Twenty Four [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	200,982	200,000
Carrying Reported Amount Fair Value Disclosure [Member] | Other Debt Obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 2,520	$ 2,402