Summary of Charges Incurred by Expense Type and Remaining Liability (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Profit Enhancement Initiative [Line Items]
Liability			$ 883	$ 2,613	$ 2,613
Cash payments			(301)		(1,463)
Non-cash adjustments			(108)		(267)
Liability	474		474		883
Employee Termination
Profit Enhancement Initiative [Line Items]
Liability			12	785	785
Cash payments			(12)		(773)
Liability					12
Operating Leases
Profit Enhancement Initiative [Line Items]
Liability			871	1,828	1,828
Cash payments			(289)		(690)
Non-cash adjustments	(40)	(180)	(108)	(180)	(267)
Liability	$ 474		$ 474		$ 871