Other Liabilities (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Financial Instruments Subject to Mandatory Redemption by Settlement Terms
Gain on asset acquisition	$ 7.7
Redeemable financial liability	174.8
Previously Reported
Financial Instruments Subject to Mandatory Redemption by Settlement Terms
Gain on asset acquisition	72.6
Restatement Adjustment
Financial Instruments Subject to Mandatory Redemption by Settlement Terms
Gain on asset acquisition	(64.9)
Other Current Liabilities
Financial Instruments Subject to Mandatory Redemption by Settlement Terms
Current portion of mandatorily redeemable financial liability	$ 33.7