Subsequent Event - Additional Information (Detail) (USD $)				1 Months Ended
	Sep. 29, 2012	Dec. 31, 2011	Sep. 24, 2011	Oct. 24, 2012 Shareholder Rights Plan
Subsequent Event [Line Items]
Dividend declared, per share amount				1
Common Stock, par value	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Dividend declared, record date				Nov. 09, 2012
Shares of preferred stock that each right entitles registered holder to purchase				0.0002
Preferred Stock, par value				$ 0.01
Series C Junior Participating Preferred Stock, purchase price per one five-thousandth of a share	$ 2.56			$ 11.50
Distribution date, number of business days following a public announcement that a person or group of affiliated or associated persons has become an "Acquiring Person,"				10 days
Distribution date, number of business days following commencement of tender offer or exchange offer that would result in a person or group of affiliated and associated persons beneficially owning 15% or more of shares of Common Stock then outstanding				10 days