Stockholders' Equity (Deficit), Accumulated Other Comprehensive Income (Loss) and Noncontrolling Interest - Change in Stockholders' Equity (Deficit) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Changes in defined benefit pension and other post-retirement benefit plans, tax	$ 0.7	$ 0.6	$ 0.3	$ 0.3
Changes in interest rate swap, tax		$ 1.2	$ 0.3	0.1
ASU 2016-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Changes due to adoption of ASC				$ 1.1

New accounting pronouncement or change in accounting principle effect of change on equity tax.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount, after reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, attributable to parent.

+ References

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Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income of defined benefit plan.

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