Stock-based Compensation Expense (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2011 years
Range of Exercise Prices, $9.02-$20.00
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 9.02
Exercise price, high end of range (in dollars per share)	$ 20.00
Exercise price range, options outstanding (in shares)	2,832
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	3.31
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 15.54
Exercise price range, options exercisable (in shares)	2,698
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 15.37
Range of Exercise Prices, $20.01-$30.00
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 20.01
Exercise price, high end of range (in dollars per share)	$ 30.00
Exercise price range, options outstanding (in shares)	1,640
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	5.13
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 28.08
Exercise price range, options exercisable (in shares)	1,585
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 28.14
Range of Exercise Prices, $30.01-$40.00
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 30.01
Exercise price, high end of range (in dollars per share)	$ 40.00
Exercise price range, options outstanding (in shares)	14,428
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7.38
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 35.70
Exercise price range, options exercisable (in shares)	7,493
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 35.11
Range of Exercise Prices, $40.01-$50.00
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 40.01
Exercise price, high end of range (in dollars per share)	$ 50.00
Exercise price range, options outstanding (in shares)	317
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9.11
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 45.36
Exercise price range, options exercisable (in shares)	50
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 44.24
Range of Exercise Prices, $50.01-$57.27
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 50.01
Exercise price, high end of range (in dollars per share)	$ 57.27
Exercise price range, options outstanding (in shares)	2,174
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9.69
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 52.15
Exercise price range, options exercisable (in shares)	175
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 53.91