Debt - Additional Information (Detail) (USD $)	1 Months Ended	6 Months Ended	12 Months Ended							12 Months Ended																						3 Months Ended												3 Months Ended																12 Months Ended								12 Months Ended				1 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2012	Nov. 30, 2011	Jun. 30, 2008	Dec. 31, 2007	Dec. 31, 2012 Condition One	Dec. 31, 2012 Condition Two	Dec. 31, 2012 6.50% notes due 2016		Dec. 31, 2011 6.50% notes due 2016		Jun. 30, 2011 6.50% notes due 2016	Dec. 31, 2012 7.50% notes due 2021		Dec. 31, 2011 7.50% notes due 2021		Jun. 30, 2011 7.50% notes due 2021	Feb. 28, 2009 Long Term Notes Issued	Dec. 31, 2012 10.125% notes due 2015		Dec. 31, 2011 10.125% notes due 2015		Feb. 28, 2009 10.125% notes due 2015	Dec. 31, 2012 10.375% notes due 2018		Dec. 31, 2011 10.375% notes due 2018		Feb. 28, 2009 10.375% notes due 2018	Jun. 30, 2011 6.30% notes due 2013	Dec. 31, 2012 6.30% notes due 2013		Dec. 31, 2011 6.30% notes due 2013		Jun. 30, 2008 6.30% notes due 2013	Dec. 31, 2012 7.00% notes due 2018		Dec. 31, 2011 7.00% notes due 2018		Jun. 30, 2008 7.00% notes due 2018	Dec. 31, 2007 Floating Rate Term Loan Due 2010	Jun. 30, 2011 5.60% notes due 2012	Dec. 31, 2012 5.60% notes due 2012		Dec. 31, 2011 5.60% notes due 2012		Dec. 31, 2007 5.60% notes due 2012	Dec. 31, 2012 6.40% notes due 2017		Dec. 31, 2011 6.40% notes due 2017		Dec. 31, 2007 6.40% notes due 2017	Dec. 31, 2012 7.15% notes due 2037		Dec. 31, 2011 7.15% notes due 2037		Dec. 31, 2007 7.15% notes due 2037	Dec. 31, 1991 Medium-term Notes	Dec. 31, 2012 Medium-term Notes Y	Dec. 31, 2011 Medium-term Notes	Nov. 30, 2007 Industrial Revenue Bonds Maturing One	Nov. 30, 2007 Industrial Revenue Bonds Maturing Two	Nov. 30, 2007 Industrial Revenue Bonds Maturing Three	Dec. 31, 2012 Other Notes	Dec. 31, 2011 Other Notes	Dec. 31, 2012 Line of Credit	Dec. 31, 2011 Line of Credit	Dec. 31, 2012 Line of Credit Minimum	Dec. 31, 2012 Line of Credit Maximum	Jul. 31, 2010 Floating Rate Term Loan Due 2011	Jun. 30, 2011 Floating Rate Term Loan Due 2011	Jun. 30, 2011 Floating Rate Term Loan Due 2015
Debt Instrument [Line Items]
Amount of final principal payment					$ 134,557,000	$ 5,000,000
Amount of facility			600,000,000
Borrowing capacity description			fluctuates with the level of eligible accounts receivable and inventory and may be less than $600,000,000 at any point in time
Interest rate margin																																																																						1.75%	2.25%
Applicable margin for LIBOR based borrowing																																																																				1.75%
Long-term notes face amount	1,100,000,000	1,100,000,000					650,000,000	1,225,000,000							500,000,000					600,000,000	400,000,000					150,000,000					250,000,000						250,000,000					400,000,000	325,000,000						300,000,000					350,000,000					250,000,000	81,000,000														450,000,000
Coupon rate of notes											6.50%				6.50%	7.50%				7.50%		10.125%				10.125%	10.375%				10.375%	6.30%	6.30%				6.30%	7.00%				7.00%		5.60%	5.60%				5.60%	6.40%				6.40%	7.15%				7.15%
Purchase of long term notes																																109,556,000												165,443,000
Outstanding amount under revolving credit facility repaid	275,000,000
Amount of outstanding balance of loan repaid																																																																								100,000,000
Recognition of unamortized deferred financing costs																																																																									2,423,000
Total consideration paid for debt		294,533,000
Premium paid for purchase of debt	19,534,000	19,534,000
Expenses related to partial termination of debt	4,711,000
Combined expense				24,245,000
Maturity period of notes, minimum																																																												3 years
Maturity period of notes, maximum																																																												30 years
Coupon rate of notes, minimum																																																												7.59%
Coupon rate of notes, maximum																																																												8.85%
Amount of notes outstanding																																																													16,000,000
Weighted-average maturity (in years)																																																													3.3
Weighted-average interest rate																																																													8.79%
Industrial revenue bonds																																																															2,250,000	1,300,000	14,000,000
Long-term Debt			2,677,003,000	2,815,439,000							515,060,000	[1]	518,293,000	[1]		600,000,000	[2]	600,000,000	[2]			152,718,000	[3]	153,464,000	[3]		248,676,000	[4]	248,526,000	[4]			140,413,000	[5]	140,352,000	[5]		399,731,000	[6]	399,693,000	[6]				0	[7]	134,508,000	[7]		349,888,000	[8]	349,869,000	[8]		239,553,000	[9]	239,545,000	[9]			16,000,000	16,000,000				964,000	1,189,000	0	0
Line of Credit Covenant Description									$ 180,000,000	$ 120,000,000
Minimum Fixed Charge Coverage Ratio										1
Line of credit usage				90.00%

[1] Includes an increase for the unamortized portion of the deferred gain realized upon the August 2011 settlement of interest rate swaps, as follows: December 31, 2012 - $15,060 thousand and December 31, 2011 - $18,293 thousand. The effective interest rate for these notes is 6.02%.

[2] The effective interest rate for these notes is 7.75%.

[3] Includes an increase for the unamortized portion of the deferred gain realized upon the August 2011 settlement of interest rate swaps, as follows: December 31, 2012 - $2,983 thousand and December 31, 2011 - $3,802 thousand. Additionally, includes decreases for unamortized discounts, as follows: December 31, 2012 - $265 thousand and December 31, 2011 - $338 thousand. The effective interest rate for these notes is 9.59%.

[4] Includes decreases for unamortized discounts, as follows: December 31, 2012 - $1,324 thousand and December 31, 2011 - $1,474 thousand. The effective interest rate for these notes is 10.62%.

[5] Includes decreases for unamortized discounts, as follows: December 31, 2012 - $30 thousand and December 31, 2011 - $92 thousand. The effective interest rate for these notes is 7.48%.

[6] Includes decreases for unamortized discounts, as follows: December 31, 2012 - $269 thousand and December 31, 2011 - $307 thousand. The effective interest rate for these notes is 7.87%.

[7] Includes decreases for unamortized discounts, as follows: December 31, 2011 - $49 thousand.

[8] Includes decreases for unamortized discounts, as follows: December 31, 2012 - $112 thousand and December 31, 2011 - $131 thousand. The effective interest rate for these notes is 7.41%.

[9] Includes decreases for unamortized discounts, as follows: December 31, 2012 - $635 thousand and December 31, 2011 - $643 thousand. The effective interest rate for these notes is 8.05%.