Deferred Income Tax Assets and Liabilities Recorded on Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deferred tax assets:
Postretirement benefits other than pensions	$ 14,900	$ 15,705
Accrued employee benefits	26,603	37,861
Operating loss carryovers	74,934	72,570
Pensions	74,521	45,213
Tax credit carryovers	37,684	49,999
Undistributed earnings of foreign subsidiaries	15,583
Other	23,280	16,097
Gross deferred tax assets	267,505	237,445
Valuation allowance	(49,562)	(36,419)	(39,802)	(41,355)
Deferred tax assets	217,943	201,026
Deferred tax liabilities:
Depreciation	(193,021)	(193,814)
Foreign currency translation adjustments	(4,933)	(6,979)
Undistributed earnings of foreign subsidiaries		(2,604)
Other	(20,348)	(17,197)
Deferred tax liabilities	(218,302)	(220,594)
Net deferred tax liabilities	(359)	(19,568)
Current deferred tax assets	4,197	9,383
Current deferred tax liabilities	(5,700)	(2,005)
Noncurrent deferred tax assets	64,512	50,957
Noncurrent deferred tax liabilities	(63,368)	(77,903)
Net deferred tax liabilities	$ (359)	$ (19,568)