Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets related to:
Inventories	$ 69.6	$ 62.6
Valuation and other reserves	34.7	22.3
Net operating loss carryforwards	9.0	10.5
Accumulated other comprehensive loss	89.4	85.2	$ 84.2
Lease liabilities	105.6	114.7
Other items, net	2.3	2.9
Gross deferred tax assets	310.6	298.2
Valuation allowance on deferred tax assets	(8.1)	(9.0)
Total net deferred tax assets	302.5	289.2
Deferred tax liabilities related to:
Property, plant and equipment	(743.3)	(700.8)
Goodwill and other intangibles	(154.6)	(151.7)
Right-of-use assets	(111.3)	(112.1)
Partnerships and joint ventures	(27.4)	(27.4)
Employee benefits	(47.4)	(30.2)
Total deferred tax liabilities	(1,084.0)	(1,022.2)
Deferred income taxes, net	$ (781.5)	$ (733.0)