Shareholders' Equity (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Shareholders' Equity [Abstract]
Common stock, shares authorized (in shares)	680,000,000	460,000,000
Shareholder Rights Agreement [Abstract]
Shareholder rights accompanying each outstanding share of the company's common stock (in number of Rights)	1
Common stock, beneficial ownership threshold to be considered an Acquiring Person (in hundredths)	5.00%
Distribution Date, description	the earlier of ten days after a public announcement that a person has become an Acquiring Person, or ten business days after a person announces or begins a tender offer in which consummation of such offer would result in a person becoming an Acquiring Person
Common shares purchaseable per Right (in shares)	0.5
Purchase price (in dollars per share)	$ 14
Purchase price (in dollars per one-half share)	$ 7.00
Redemption price (in dollars per Right)	$ 0.001