Leases - Lease Cost (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2019
Components of lease cost
Amortization of right-of-use assets		$ 0.3
Total finance lease cost		0.3
Operating lease cost		24.9
Short term lease cost		2.2
Variable lease cost		3.5
Sublease income		(1.2)
Total lease cost		$ 29.7
ASU 2016-02
Leases and Lease cost
Practical expedients	true
Lease assets	$ 75.5
Lease liabilities	$ 77.9