Shareholder Rights Plan (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Shareholder Rights Plan
Common stock, par value	$ 0.01	$ 0.01
Exercise price of warrants or rights	160
Date from which warrant or rights are exercisable	May 31, 2002
Expiration date of warrants or rights outstanding	May 30, 2012