Components of Noncurrent Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Other Liabilities [Line Items]
Pension and retiree medical obligations	$ 95,061	$ 96,853
Liability for uncertain tax positions	5,014	4,989
Deferred revenue	6,811	6,534
Contingent consideration for acquisition		5,515
Other	13,866	14,484
Total other noncurrent liabilities	$ 120,752	$ 128,375