Utilization of Components of Accrued Exit Costs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Restructuring Cost and Reserve [Line Items]
Exit Costs Beginning Balance	$ 5,462
Amount provided for during period	1,348	5,464
Amount paid during period	(4,576)	(2)
Exit Costs Ending Balance	2,234	5,462
Termination benefits
Restructuring Cost and Reserve [Line Items]
Exit Costs Beginning Balance	4,843
Amount provided for during period	980	4,843
Amount paid during period	(3,589)
Exit Costs Ending Balance	2,234	4,843
Other associated costs
Restructuring Cost and Reserve [Line Items]
Exit Costs Beginning Balance	619
Amount provided for during period	368	621
Amount paid during period	(987)	(2)
Exit Costs Ending Balance		$ 619