Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Environmental liabilities	$ 3.9	$ 3.9
Environmental remediation liabilities - discounted	$ 23.8	22.0
Accrual for environmental loss contingencies - weighted-average discount rate	3.50%
Environmental remediation liabilities - undiscounted	$ 63.3	$ 59.5
Potential revision on future environmental remediation costs before tax	$ 16.0