Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accumulated Comprehensive Income Loss [Line Items]
Foreign currency translation	$ 131,084	$ 107,238
Unrecognized net actuarial loss, net of tax	(644,244)	(617,623)
Unrecognized prior service credit, net of tax	11,668	28,347
Total accumulated other comprehensive loss	$ (501,492)	$ (482,038)