Stockholders' Equity (Detail) (USD $)	9 Months Ended
	Sep. 30, 2011		Dec. 31, 2010
Stockholders' Equity [Line Items]
Number of rights per common share	1
Preferred stock, par value	$ 0.01	[1]	$ 0.01	[1]
Minimum percentage of equity ownership	10.00%		80.00%
Rights Expiration date	September 6, 2021
Minimum percentage of assets or earning power sold	50.00%
Maximum percentage of equity ownership	50.00%
Redemption price per right	$ 0.01
Series A Junior Participating Preferred Stock [Member]
Stockholders' Equity [Line Items]
Preferred stock, par value	$ 0.01
Purchase price per right entitled share	$ 45.00
Number of share per right	0.001
Right, exchange ratio	0.001
Common Stock [Member]
Stockholders' Equity [Line Items]
Right, exchange ratio	1

[1] Restated