Stockholders' Equity - Summary of Stock Options Granted (Details) (USD $)	65 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 April 17, 2012	Sep. 30, 2012 April 19, 2011	Sep. 30, 2012 April 20, 2010	Sep. 30, 2012 April 21, 2009	Sep. 30, 2012 April 15, 2008	Sep. 30, 2012 April 17, 2007
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted	7,895,000	1,235,000	410,000	530,000	790,000	550,000	4,380,000
Option exercise (strike) price		$ 54.00	$ 35.00	$ 30.00	$ 27.00	$ 27.00	$ 22.50
Closing stock price on date of grant		$ 49.01	$ 31.78	$ 27.13	$ 17.61	$ 24.35	$ 20.15
Options outstanding	5,176,092	1,192,500	380,000	380,000	590,000	305,167	2,328,425
Options vested	1,411,342	0	0	0	0	135,167	1,276,175