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Significant Accounting Policies - Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Equity [Abstract] |  |  |  |
Balance at beginning of period, Pension and Postretirement Benefit Plans | $ 83.6 | $ 82.4 | $ 85.2 | $ 84.2
Tax effect of other comprehensive earnings, Pension and Postretirement Benefit Plans | (1.1) | (0.9) | (2.7) | (2.7)
Balance at end of period, Pension and Postretirement Benefit Plans | $ 82.5 | $ 81.5 | $ 82.5 | $ 81.5

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- Definition Accumulated other comprehensive loss, noncurrent deferred tax assets, other comprehensive earnings, tax effect, pension and postretirement benefit plans. + References No definition available. + Details
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- Definition Accumulated other comprehensive loss, noncurrent deferred tax assets, pension and postretirement benefit plans. + References No definition available. + Details
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- References No definition available. + Details
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