Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Accrued liabilities and reserves	$ 42.9	$ 43.9
Pension and other post-retirement compensation and benefits	25.2	35.7
Employee compensation and benefits	21.8	39.2
Tax loss and credit carryforwards	724.7	670.5
Other assets	4.4	0.0
Total deferred tax assets	819.0	789.3
Valuation allowance	711.9	656.2
Deferred tax assets, net of valuation allowance	107.1	133.1
Deferred tax liabilities
Property, plant and equipment	7.1	3.7
Goodwill and other intangibles	179.7	190.6
Other liabilities	0.0	18.4
Deferred Tax Liabilities, Gross	186.8	212.7
Total deferred tax liabilities	$ 79.7	$ 79.6