Utilization of Components of Accrued Exit Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Restructuring Cost and Reserve [Line Items]
Exit Costs Beginning Balance	$ 2,234
Amount provided for during period	118
Amount paid during period	(1,877)
Exit Costs Ending Balance	475
Termination benefits
Restructuring Cost and Reserve [Line Items]
Exit Costs Beginning Balance	2,234
Amount provided for during period	118
Amount paid during period	(1,877)
Exit Costs Ending Balance	$ 475