Shareholders' Equity - Schedule of Stock Options Activity (Details) - Stock Options $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock, Outstanding, Beginning Balance (in shares) | shares	0.6
Stock, Exercised (in shares) | shares	(0.2)
Stock, Outstanding, Ending Balance (in shares) | shares	0.4
Stock, Exercisable (in shares) | shares	0.3
Stock, Expected to vest (in shares) | shares	0.1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Beginning Balance (in USD per share) | $ / shares	$ 15.48
Weighted Average Exercise Price, Exercised (in USD per share) | $ / shares	6.54
Weighted Average Exercise Price, Ending Balance (in USD per share) | $ / shares	18.86
Weighted Average Exercise Price, Exercisable (in USD per share) | $ / shares	17.09
Weighted Average Exercise Price, Expected to vest (in USD per share) | $ / shares	$ 23.06
Weighted Average Remaining Contractual Life, Outstanding	4 years 7 months 6 days
Weighted Average Remaining Contractual Life, Exercisable	4 years 9 months 18 days
Weighted Average Remaining Contractual Life, Expected to vest	4 years 2 months 12 days
Intrinsic Value, Outstanding | $	$ 5.1
Intrinsic Value, Exercisable | $	4.1
Intrinsic Value, Expected to vest | $	$ 1.0