Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Valuation Allowance [Line Items]
Gross deferred federal, state and local tax benefit	$ 13.0		$ 19.5
Deferred federal, state and local tax benefit	13.0		21.2
Deferred tax assets, tax deferred expense, employee compensation	(1.7)		(1.7)
Change in valuation allowance	13.3		20.0
Valuation allowance	$ 370.2		370.2		$ 336.4
Federal and State
Valuation Allowance [Line Items]
Deferred federal, state and local tax benefit		$ 46.4		$ 55.9
Change in valuation allowance		$ 30.3	21.7	$ 54.9
ASC 842
Valuation Allowance [Line Items]
Change in valuation allowance			$ 13.8