Stock-based Compensation Expense (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2011
Range of Exercise Prices, $8.68-$20.00
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 8.68
Exercise price, high end of range (in dollars per share)	$ 20.00
Exercise price range, options outstanding (in shares)	3,050
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	3.61
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 15.54
Exercise price range, options exercisable (in shares)	2,839
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 15.30
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)	1,862
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	5.11
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 27.81
Exercise price range, options exercisable (in shares)	1,734
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 27.85
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)	15,063
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7.74
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 35.69
Exercise price range, options exercisable (in shares)	7,110
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 35.04
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)	277
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8.56
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 45.28
Exercise price range, options exercisable (in shares)	54
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 43.31
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)	337
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9.88
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 54.52
Exercise price range, options exercisable (in shares)	164
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 53.81