Stock-based Compensation Expense (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Exercise Price Range from Dollars 9.07 to Dollars 20.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 9.07
Exercise price, high end of range (usd per share)	$ 20.00
Exercise price range, options outstanding (in shares)	887
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	3 years 0 months 18 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 15.33
Exercise price range, options exercisable (in shares)	887
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 15.33
Exercise Price Range from Dollars 20.01 to Dollars 30.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 20.01
Exercise price, high end of range (usd per share)	$ 30.00
Exercise price range, options outstanding (in shares)	1,394
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	6 years 1 month 17 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 29.32
Exercise price range, options exercisable (in shares)	1,052
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 29.14
Exercise Price Range from Dollars 30.01 to Dollars 40.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 30.01
Exercise price, high end of range (usd per share)	$ 40.00
Exercise price range, options outstanding (in shares)	11,913
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	6 years 7 months 10 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 36.11
Exercise price range, options exercisable (in shares)	7,905
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 35.41
Exercise Price Range from Dollars 40.01 to Dollars 50.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 40.01
Exercise price, high end of range (usd per share)	$ 50.00
Exercise price range, options outstanding (in shares)	5,333
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9 years 6 months 11 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 46.34
Exercise price range, options exercisable (in shares)	341
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 47.41
Exercise Price Range from Dollars 50.01 to Dollars 60.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 50.01
Exercise price, high end of range (usd per share)	$ 60.00
Exercise price range, options outstanding (in shares)	2,268
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8 years 5 months 16 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 53.44
Exercise price range, options exercisable (in shares)	926
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 54.03
Exercise Price Range From Dollars 60.01 to 64.30 [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 60.01
Exercise price, high end of range (usd per share)	$ 64.30
Exercise price range, options outstanding (in shares)	53
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8 years 11 months 1 day
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 63.31
Exercise price range, options exercisable (in shares)	11
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 63.23