Other Noncurrent Assets - Other Noncurrent Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Other noncurrent assets:
Land held for development	$ 116.2	$ 125.3
Operating lease right-of-use assets	27.0	29.0
Restricted cash and cash equivalents	33.4	33.0
IBNR receivables	7.9	8.5
Marketable securities	5.5	6.2
Pension asset	7.8	7.4
Note receivables - OPA	27.6	8.8
Other	8.4	11.9
Total	$ 233.8	$ 230.1