Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Tax Reform Act Tax Expense Charge		$ 92.0
Gross amount of the net operating loss carryforwards	$ 362.7		$ 362.7
Net operating loss carryforwards	42.0	41.1	42.0	$ 41.1
Potential benefits	9.0		9.0
Interest and penalties included in income tax expense				(0.3)	$ 0.1
Accrued penalties and interest	1.8	0.8	1.8	$ 0.8
Currently remaining unrecognized tax positions that may be recognized by the end of following year			$ 1.4
Tax Cuts and Jobs Act of 2017
Operating Loss Carryforwards [Line Items]
Tax Reform Act Tax Expense Charge	$ 2.0	$ 92.0