Income Taxes - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2015	Nov. 30, 2014
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits	$ 7.1	$ 4.4				$ 29.5				$ 4.4	$ 29.5	$ 6.7	$ 6.8
Effective income tax rate - provision (benefit)	(22.20%)									(110.60%)	(38.40%)	1.90%
Income (loss) from continuing operations before income taxes	$ 9.0	22.9	$ 18.6	$ 36.2	$ 9.2	$ 34.4	$ (25.3)	$ 11.5	$ 8.6	$ 86.9	$ 29.2	$ (15.9)
Income tax expense from remeasurement of deferred tax assets and liabilities related to Tax Cuts and Jobs Act										$ 64.6
New legislation - tax rate changes	0.00%									74.40%	0.00%	0.00%
Unrecognized tax benefits, effect in tax rate		4.2								$ 4.2
Accrued interest and penalties related to uncertain tax positions		0.3								0.3
Possible reduction in unrecognized tax benefits and related interest (less than)		0.5								0.5
Valuation Allowances and Reserves, Balance		1.7								1.7
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		33.0								33.0
State | California
Operating Loss Carryforwards [Line Items]
Tax credit carryforward		3.4								3.4
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		20.4								20.4
Tax credit carryforward		3.4								3.4
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		$ 8.0								$ 8.0