Income Taxes - Deferred Income Taxes (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets
Income tax loss carryforwards	$ 6.6	$ 17.0
Other accrued liabilities	1.1	1.7
Employee benefits related	4.3	1.9
Insurance related	0.7	0.7
Goodwill	0.5	0.5
Intangibles	0.5	0.5
Inventories	1.3	1.4
Accounts receivables	0.5	0.7
Leases	9.4	8.4
Other, assets		0.1
Gross deferred tax assets	24.9	32.9
Valuation allowance	(6.0)	(18.1)
Deferred Tax Assets, Total	18.9	14.8
Liabilities
Property, plant and equipment	1.1	0.3
Insurance related	0.6	0.6
LIFO	7.4	5.6
Leases	9.4	8.3
Gross deferred tax liabilities	18.5	14.8
Deferred Tax Liabilities, Total	$ 18.5	$ 14.8