Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended			104 Months Ended
	Jan. 16, 2019	Jan. 02, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Subsequent Event [Line Items]
Dividends paid (in dollars per share)			$ 1.54	$ 1.28	$ 1.2
Options Granted (in shares)						6,382,417
Options vesting and exercisable period, maximum			8 years
Options termination period			9 years
Total intrinsic value of stock options exercised			$ 4.2	$ 6.9	$ 23.2
Total unrecognized stock-based compensation expense			$ 13.7			$ 13.7
Weighted average period over which total unrecognized stock-based compensation expense will be recognized			3 years 10 months 20 days
Total grant date fair value of stock options vested			$ 5.3	4.2	7.1
Total stock-based compensation expense			$ 5.1	$ 5.2	$ 4.1
Subsequent Event
Subsequent Event [Line Items]
Dividend declared (in dollars per share)	$ 0.43
Options Granted (in shares)		643,957
Option Exercise (Strike) Price (in dollars per share)		$ 52
Closing Stock Price on Date of Grant (in dollars per share)		$ 51.41
Non-employee Director Options Elected (in shares)		14,505
Non-employee Director Option Exercise (Strike) Price (in dollars per share)		$ 52