Stock-based Compensation Expense (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012 Y
Range of Exercise Prices, $9.07-$20.00
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 9.07
Exercise price, high end of range (in dollars per share)	$ 20.00
Exercise price range, options outstanding (in shares)	1,163
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	3.21
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 15.53
Exercise price range, options exercisable (in shares)	1,163
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 15.53
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)	1,434
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	6.60
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 29.29
Exercise price range, options exercisable (in shares)	1,023
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 29.08
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)	12,882
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7.17
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 36.10
Exercise price range, options exercisable (in shares)	7,204
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 35.18
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)	2,327
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9.61
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 48.11
Exercise price range, options exercisable (in shares)	70
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 44.55
Range of Exercise Prices, $50.01-$60.00
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)	$ 60.00
Exercise price range, options outstanding (in shares)	2,355
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8.97
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 53.37
Exercise price range, options exercisable (in shares)	691
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 54.43
Range of Exercise Prices, $60.01-$64.30
Stock options outstanding and exercisable
Exercise price, low end of range (in dollars per share)	$ 60.01
Exercise price, high end of range (in dollars per share)	$ 64.30
Exercise price range, options outstanding (in shares)	65
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9.63
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 63.10
Exercise price range, options exercisable (in shares)	4
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 63.10