Stockholders' Equity (Stock Options Granted) (Details) (USD $)		9 Months Ended
	Apr. 19, 2011	Sep. 30, 2011 April 19, 2011 [Member]	Sep. 30, 2011 April 20, 2010 [Member]	Sep. 30, 2011 April 21, 2009 [Member]	Sep. 30, 2011 April 15, 2008 [Member]	Sep. 30, 2011 April 17, 2007 [Member]
Options granted		410,000	530,000	790,000	550,000	4,380,000
Option exercise (strike) price	$ 35.00	$ 35.00	$ 30.00	$ 27.00	$ 27.00	$ 22.50
Closing stock price on date of grant	$ 31.78	$ 31.78	$ 27.13	$ 17.61	$ 24.35	$ 20.15
Options outstanding		410,000	400,000	600,000	360,000	3,432,550
Options vested		0	0	0	0	1,725,550