Leases - Summary of Location and Amount of Lease Assets and Lease Liabilities (Detail) - USD ($) $ in Millions		Sep. 30, 2021	Dec. 31, 2020
Assets
Right of use assets		$ 204.7	$ 108.3
Finance lease assets	[1]	42.2	45.5
Total lease assets		246.9	153.8
Liabilities
Operating lease liabilities, current		25.4	20.7
Finance lease liabilities, current		13.2	9.0
Operating lease liabilities, noncurrent		176.6	93.0
Finance lease liabilities, noncurrent		$ 16.5	$ 14.3
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		Other noncurrent liabilities	Other noncurrent liabilities
Total lease liabilities		$ 231.7	$ 137.0

[1] Finance lease assets were recorded net of accumulated amortization of $16.6 million and $21.0 million as of September 30, 2021 and December 31, 2020, respectively.