DEBT (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Long-term Debt	$ 586,430	$ 396,644
Current portion of long-term debt and short-term debt	2,502	2,602
Long-term debt	583,928	394,042
Industrial Revenue Bonds, due 2012-2023 [Member]
Debt Instrument [Line Items]
Long-term Debt	9,004	9,102
Revolving Credit Agreement, due 2012 [Member]
Debt Instrument [Line Items]
Long-term Debt	0	110,000
Senior Notes Five Seventy Four [Member]
Debt Instrument [Line Items]
Long-term Debt	125,024	125,038
Senior Notes Five Fifty One [Member]
Debt Instrument [Line Items]
Long-term Debt	150,000	150,000
Senior Notes Three Eighty Four [Member]
Debt Instrument [Line Items]
Long-term Debt	100,000
Senior Notes Four Twenty Four [Member]
Debt Instrument [Line Items]
Long-term Debt	200,000
Other Debt [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 2,402	$ 2,504