Supplemental Financial Information - Accumulated Other Comprehensive Loss, Net of Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated net foreign currency translation adjustments, Beginning Balance	$ 42,138
Accumulated net unrealized (loss)/gain on investments, Beginning Balance	5,942
Accumulated net unrealized (loss)/gain on derivatives, Beginning Balance	(2,551)
Accumulated actuarial loss on pension and post-retirement plans, Beginning Balance	(578,757)
Total accumulated other comprehensive income, Beginning Balance	(533,228)
Accumulated net foreign currency translation adjustments, Other Comprehensive Loss	(2,257)
Accumulated net unrealized (loss)/gain on investments, Other Comprehensive Loss	(1,458)
Accumulated net unrealized (loss)/gain on derivatives, Other Comprehensive Loss	2,775
Accumulated actuarial loss on pension and post-retirement plans, Other Comprehensive Loss	(44,162)
Other comprehensive loss	(45,102)	(214,963)	(38,624)
Accumulated net foreign currency translation adjustments, Ending Balance	39,881	42,138
Accumulated net unrealized (loss)/gain on investments, Ending Balance	4,484	5,942
Accumulated net unrealized (loss)/gain on derivatives, Ending Balance	224	(2,551)
Accumulated actuarial loss on pension and post-retirement plans, Ending Balance	(622,919)	(578,757)
Total accumulated other comprehensive income, Ending Balance	$ (578,330)	$ (533,228)