Other Current Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 83.4	$ 84.1
Other Receivables, Gross, Current	18.9	15.2
Income Taxes Receivable, Current	17.7	19.0
Other investments	10.4	30.7
Marketable securities (Note 2)	2.8	2.9
Contract assets	1.5	1.4
Deferred financing fees (Note 10)	0.5	0.5
Other	15.9	16.4
Total other current assets	$ 151.1	$ 170.2