Shareholder Rights Agreement (Details) (USD $)		36 Months Ended
	Aug. 06, 1996 1996 Shareholder Rights Agreement [Member]	Oct. 21, 2015 2012 Amended Shareholder Rights Agreement [Member]
Common stock exercise price per share for each right	$ 80.00
Common stock exercise price per one half share	$ 40.00
Percent of outstanding common shares required to exercise purchase rights	20.00%
Rights redemption price	$ 0.001
Extended term of rights, expiration date		Oct. 21, 2015