Income Taxes - Summary of Changes in Valuation Allowance (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at End of Period		$ 1.7
Tax Valuation Allowance of Deferred Tax Assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 1.7	1.7	$ 1.2	$ 2.6
Tax Valuation Allowance Charged to Income Tax Provision	0.0	0.0	0.5	0.6
Tax Valuation Allowance Credited to Income Tax Provision	(0.5)	0.0	0.0	(1.5)
Balance at End of Period	$ 1.2	$ 1.7	$ 1.7	$ 1.7