Stockholders' Deficit (Details 5) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Compensation Plans
Number of shares issued	194,453	193,657	390,000
Stock compensation expense	$ 69.9	$ 62.2	$ 38.4
Shares Available For Grant
Shares Available for Grant Beginning Balance (in shares)	1,001,523
Shares Available for Grant Ending Balance (in shares)	834,433	1,001,523
Shares Subject to Outstanding Options, Shares
Outstanding at the beginning of the period (in shares)	398,477
Outstanding at the end of the period (in shares)	565,567	398,477
Employee Stock Purchase Plan
Stock Compensation Plans
Employment period for eligibility to participate in the plan	1 month
Number of shares issued	194,453	193,657	390,000
Stock compensation expense	$ 2.4	$ 1.9	$ 1.5
Remaining shares available	711,158
Employee Stock Purchase Plan | Minimum
Stock Compensation Plans
Number of employee working hours per week for eligibility to participate in the plan	20 hours
Restricted Stock Units (RSUs)
Shares Available For Grant
Granted (in shares)	(206,614)
Cancelled (in shares)	34,566
Shares Subject to Outstanding Options, Shares
Granted (in shares)	206,614
Cancelled (in shares)	(34,566)
Shares Subject to Outstanding Options, Weighted Average Exercise Price
Granted (in dollars per share)	$ 79.52
Cancelled (in dollars per share)	$ 62.50
Performance Stock Units (PSUs)
Stock Compensation Plans
Stock compensation expense	$ 0.0
Shares Available For Grant
Cancelled (in shares)	4,958
Shares Subject to Outstanding Options, Shares
Granted (in shares)		55,326
Cancelled (in shares)	(4,958)
Shares Subject to Outstanding Options, Weighted Average Exercise Price
Cancelled (in dollars per share)	$ 64.55