Share Based and Deferred Compensation (Details) (USD $)	6 Months Ended
	Jun. 30, 2011
Option activity
Outstanding at January 1, 2011, shares	3,116,611
Granted, shares	603,241
Exercised, shares	(76,887)
Outstanding at June 30, 2011, shares	3,642,965
Vested/Exercisable at June 30, 2011, shares	2,331,021
Outstanding at January 1, 2011, Weighted Average Exercise Price	$ 14.56
Granted, Weighted Average Exercise Price	$ 11.89
Exercised, Weighted Average Exercise Price	$ 2.91
Outstanding at June30, 2011, Weighted Average Exercise Price	$ 14.37
Vested/Exercisable at June 30, 2011, Weighted Average Exercise Price	$ 16.75
Outstanding at January 1, 2011, Weighted Average Remaining Contractual Term	7.81
Granted, Weighted Average Remaining Contractual Term (in years)	9.68
Outstanding at June 30, 2011, Weighted Average Remaining Contractual Term	7.70
Vested/Exercisable at June 30, 2011, Weighted Average Remaining Contractual Term	7.05
Outstanding at January 1, 2011, Aggregate Intrinsic Value	$ (9,080,625)
Granted, Aggregate Intrinsic Value	(180,972)
Outstanding at June 30, 2011, Aggregate Intrinsic Value	(10,115,971)
Vested/Exercisable at June 30, 2011, Aggregate Intrinsic Value	$ (11,802,863)