Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Beginning accumulated other comprehensive income (loss), Postretirement Benefit Liability Adjustments	$ 2,510		$ 2,647
Other comprehensive income before reclassifications, Postretirement Benefit Liability Adjustments
Amounts reclassified from accumulated other comprehensive income (loss), Postretirement Benefit Liability Adjustments	(34)	1,044	(171)	(311)
Net current period other comprehensive (loss) income, Postretirement Benefit Liability Adjustments	(34)		(171)
Ending accumulated other comprehensive income (loss), Postretirement Benefit Liability Adjustments	2,476		2,476
Beginning accumulated other comprehensive income (loss), Translation Adjustments	5,911		14,080
Other comprehensive income before reclassifications, Translation Adjustments	4,203		(3,966)
Amounts reclassified from accumulated other comprehensive income (loss), Translation Adjustments
Net current period other comprehensive (loss) income, Translation Adjustments	4,203		(3,966)
Ending accumulated other comprehensive income (loss), Translation Adjustments	10,114		10,114
Beginning accumulated other comprehensive income (loss), Other Adjustments	(77)		(77)
Other comprehensive income before reclassifications, Other Adjustments
Amounts reclassified from accumulated other comprehensive income (loss), Other Adjustments
Net current period other comprehensive (loss) income, Other Adjustments
Ending accumulated other comprehensive income (loss), Other Adjustments	(77)		(77)
Beginning accumulated other comprehensive income (loss)	8,344		16,650
Other comprehensive income before reclassifications	4,203		(3,966)
Amounts reclassified from accumulated other comprehensive income (loss)	(34)		(171)
Net current period other comprehensive (loss) income			(3,991)	(3,251)
Ending accumulated other comprehensive income (loss)	12,513		12,513
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Net current period other comprehensive (loss) income	$ 4,169		$ (4,137)