Commitments and Contingencies (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 20, 2017	Aug. 31, 2013	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Long-term Purchase Commitment [Line Items]
Minimum future payment commitments			$ 47.7		$ 47.7
New operating leases, future minimum payments, remainder of fiscal year			1.2		$ 1.2
New operating leases, terms of payment					with the remainder due in 2021 through 2028
Rent expense			2.8	$ 2.5	$ 7.9	$ 7.5
Financing obligation, lease term		120 months
Non-cancellable purchase commitments			423.1		423.1
Restricted deposits			22.0		22.0		$ 36.9
Recommended civil penalty	$ 307.0
Contract with manufacturers and suppliers
Long-term Purchase Commitment [Line Items]
Non-cancellable purchase commitments			370.4		370.4
Land
Long-term Purchase Commitment [Line Items]
Lease expense under financing obligation			$ 0.3	$ 0.3	$ 1.0	$ 1.0