Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Post-retirement obligations	$ 5.7	$ 6.2
Tax credits	1.8	1.8
Expenses not currently deductible	28.7	28.5
Net operating loss carryover	6.0	5.9
Debt and derivative instruments	8.6	2.2
Operating lease liabilities	12.1	9.2
Other	15.2	3.2
Total deferred tax assets	78.1	57.0
Valuation allowance for deferred tax assets	(4.3)	(4.8)
Net deferred tax assets	73.8	52.2
Deferred tax liabilities:
Property, plant and equipment	35.7	38.1
Intangible assets	256.6	343.4
Goodwill	9.9	9.5
Operating lease right of use asset	11.6	8.8
Other	8.2	7.1
Total deferred liabilities	322.0	406.9
Net deferred tax liabilities	$ 248.2	$ 354.7