Income Taxes - Deferred Income Taxes (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets
Income tax loss carryforwards	$ 17.7	$ 15.4
Other accrued liabilities	1.3	3.4
Employee benefits related	0.9	2.6
Property, plant and equipment		1.3
Insurance related	1.0	0.9
Goodwill	0.3	0.6
Inventories	1.1	1.2
Accounts receivables	0.2	0.2
Other, assets	0.5	0.3
Gross deferred tax assets	23.0	25.9
Valuation allowance	(7.1)	(6.4)
Deferred Tax Assets, Total	15.9	19.5
Liabilities
Property, plant and equipment	0.1
LIFO	5.8	8.6
Other, liabilities	0.3	0.6
Gross deferred tax liabilities	6.2	9.2
Deferred Tax Liabilities, Total	$ 6.2	$ 9.2