Investment in Affiliates and Other Assets - Investment in Affiliates and Other Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Other Noncurrent Assets [Line Items]
Investment in affiliates	$ 89.1	$ 102.3
Other assets:
Land held for development	162.3	158.1
Restricted cash	13.8	33.3
Deferred financing costs	7.4	2.6
IBNR receivables	7.1	6.9
Capital lease deposit	6.2	6.2
Intangible assets	5.1	5.2
Pension asset	1.2	0.6
Other	30.9	64.9
Total	288.8	337.3
Capitalized Operating Permits
Other assets:
Waste disposal site operating permits, net	54.8	59.5
LPC | TiO2 manufacturing joint venture
Other Noncurrent Assets [Line Items]
Investment in affiliates	$ 89.1	$ 102.3