Other Comprehensive Income - Changes in Accumulated Other Comprehensive Loss by Component (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Beginning balance, Pension and Other Post-Retirement Benefits	$ (632,576)
Other comprehensive loss before reclassifications, Pension and Other Post-Retirement Benefits, net of tax	0
Amounts reclassified from accumulated other comprehensive loss, Pension and Other Post-Retirement Benefits, net of tax	11,778
Net current period other comprehensive income (loss), Pension and Other Post-Retirement Benefits	11,778
Ending balance, Pension and Other Post-Retirement Benefits	(620,798)
Beginning balance, Foreign Currency Items	131,084
Other comprehensive loss before reclassifications, Foreign Currency Items, net of tax	(8,220)	18,677
Amounts reclassified from accumulated other comprehensive loss, Foreign Currency Items, net of tax
Net current period other comprehensive income (loss), Foreign Currency Items	(8,220)
Ending balance, Foreign Currency Items	122,864
Beginning balance	(501,492)
Other comprehensive loss before reclassifications, net of tax	(8,220)
Amounts reclassified from accumulated other comprehensive loss, net of tax	11,778
Net current period other comprehensive income (loss)	3,558	28,519
Ending balance	$ (497,934)