Other Noncurrent Assets - Other Noncurrent Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Other noncurrent assets:
Land held for development	$ 150.8	$ 157.2
Restricted cash	22.9	19.6
IBNR receivables	7.2	7.0
Capital lease deposit	6.2	6.2
Intangible assets		5.1
Pension asset	1.9	1.7
Other	15.2	11.8
Total	248.4	256.7
Waste Management
Other noncurrent assets:
Restricted cash	20.3	16.2
Waste Management | Capitalized Operating Permits
Other noncurrent assets:
Waste disposal site operating permits, net	$ 44.2	$ 48.1