Mandatorily Redeemable Convertible Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	11 Months Ended	12 Months Ended
	Nov. 30, 2010	Nov. 30, 2011	Dec. 31, 2009	Nov. 30, 2011 Series A Preferred Stock [Member] Dividend	Feb. 28, 2006 Series A Preferred Stock [Member]
Dividends Payable [Line Items]
Purchase of Series A convertible preferred stock					$ 125.0
Dividend of Series A convertible preferred stock				0.0325
Number of common stock shares to which Series A preferred stock is convertible	4,105,000	4,108,000	4,105,000	4,110,128
Mandatorily Redeemable Convertible Preferred Stock (Textual) [Abstract]
Mandatory redeemable preferred stock price per share		$ 1,000
Effective conversion price per share		$ 30.41
Preferred stock, shares authorized		10,000,000
Preferred stock, shares issued		125,000
Preferred stock, shares outstanding		125,000