Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Future Minimum Lease Payments under These Non-cancelable Operating Leases

The approximate future minimum lease payments under these non-cancelable operating leases at December 31, 2017 are as follows (in millions):

	Amount
2018	$	9.6
2019		9.1
2020		9.2
2021		7.1
2022		6.1
Thereafter		25.4
	$	66.5