Deferred Tax Assets Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Income Tax Assets And Liabilities [Line Items]
Employee and retiree benefit plans	$ 38,401	$ 38,626
Depreciation and amortization	(170,630)	(213,002)
Inventories	10,851	10,274
Allowances and accruals	7,629	14,103
Interest rate exchange agreement	20,856	23,714
Other	7,059	10,033
Net deferred tax liabilities	$ (85,834)	$ (116,252)