Change in Accumulated Other Comprehensive Income, Net of Tax (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Beginning of the year	$ (71,210)	$ (58,448)
Additional prior service cost incurred during the year		171
Actuarial gains (losses) incurred during the year	(42,139)	(11,861)
Translation gains (losses) incurred during the year	118	(75)
Transition obligation		8
Unrecognized prior service cost (benefit)	(16)	(12)
Actuarial gains	354	(993)
End of the year	$ (112,893)	$ (71,210)