Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	$ 32.9	$ 15.0
Term Deposits	1.1	6.8
Interest Rate Swap	1.2	0.5
Total Assets Measured at Fair Value	35.2	22.3
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	32.9	15.0
Total Assets Measured at Fair Value	32.9	15.0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Term Deposits	1.1	6.8
Interest Rate Swap	1.2	0.5
Total Assets Measured at Fair Value	$ 2.3	$ 7.3