Stock Based Compensation (Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 years
Stock Based Compensation [Abstract]
Options, Beginning of Year	3,660,634
Options, Exercised	(263,600)
Options, Forfeited	(70,750)
Options, Expired	(53,984)
Options, End of Year	3,272,300
Options, Exercisable at End of Year	2,641,475
Options, Beginning of Year, Weighted Average Exercise Price	$ 32.22
Options, Exercised, Weighted Average Exercise Price	$ 23.68
Options, Forfeited, Weighted Average Exercise Price	$ 31.65
Options, Expired, Weighted Average Exercise Price	$ 40.98
Options, End of Year, Weighted Average Exercise Price	$ 32.78
Options, Exercisable at End of Year, Weighted Average Exercise Price	$ 32.91
Options, Outstanding at December 31, 2011, Weighted Average Remaining Years Contractual Term	5.9
Options, Exercisable at December 31, 2011, Weighted Average Remaining Years Contractual Term	5.4
Options, Outstanding at December 31, 2011, Aggregate Intrinsic Value	$ 8,614,956
Options, Exercisable at December 31, 2011, Aggregate Intrinsic Value	$ 7,918,875