Mandatorily Redeemable Convertible Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012 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	4,110,000	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