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Asbestos - Additional Information (Detail) |  | 3 Months Ended | 12 Months Ended | 60 Months Ended |  |  |
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Jul. 01, 2019 USD ($) | Mar. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2017 AUD ($) | Mar. 31, 2017 USD ($) | Mar. 31, 2016 USD ($) | Mar. 31, 2019 USD ($) | Mar. 31, 2018 USD ($) | Mar. 31, 2017 USD ($) | Mar. 31, 2019 USD ($) | Mar. 31, 2019 AUD ($) | Mar. 31, 2019 AUD ($) | Mar. 31, 2018 AUD ($) | Jul. 31, 2017 AUD ($)
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Asbestos adjustments |  |  | $ 43,600,000 | $ 56,800,000 |  |  | $ 22,000,000 | $ 156,400,000 | $ (40,400,000) |  |  |  |  |
Discounted (but inflated) central estimate lower range value |  |  |  |  |  |  | 1,000,000,000 |  |  | $ 1,000,000,000 |  | $ 1,400,000,000 |  |
Discounted (but inflated) central estimate high range value |  |  |  |  |  |  | 2,200,000,000 |  |  | 2,200,000,000 |  | 3,100,000,000 |  |
Undiscounted (but inflated) central estimate lower range value |  |  |  |  |  |  | 1,100,000,000 |  |  | 1,100,000,000 |  | 1,600,000,000 |  |
Undiscounted (but inflated) central estimate high range value |  |  |  |  |  |  | 2,800,000,000 |  |  | 2,800,000,000 |  | 3,900,000,000 |  |
Payment to fund |  |  |  |  |  |  | 103,000,000 | 102,200,000 | $ 91,100,000 | 472,100,000 | $ 595,300,000 |  |  |
Net cash provided by operating activities |  | $ 295,000,000 |  |  | $ 292,100,000 | $ 260,400,000 | 287,600,000 |  |  |  |  |  |  |
Restricted short-term investments - Asbestos |  | 38,400,000 |  |  |  |  | 17,700,000 | 38,400,000 |  | 17,700,000 |  | 25,000,000 | $ 50,000,000 | $ 100,000,000
Adjustment to Restricted Short-Term Investments Asbestos |  |  |  |  |  |  | 0 |  |  |  |  |  |  |
Secured standby loan facility maximum borrowing capacity |  |  |  |  |  |  | $ 227,100,000 |  |  | $ 227,100,000 |  | $ 320,000,000.0 |  |
Maturity date of secured standby loan facility |  |  |  |  |  |  | Nov. 01, 2030 |  |  |  |  |  |  |
Loan facility, outstanding balance |  | $ 0 |  |  |  |  |  | $ 0 |  |  |  |  |  |
Rate of interest of Benchmark Bonds (as percent) |  |  |  |  |  |  | 6.00% |  |  |  |  |  |  |
Maturity date of Benchmark Bonds |  |  |  |  |  |  | May 01, 2020 |  |  |  |  |  |  |
AICF Funding |  |  |  |  |  |  |  |  |  |  |  |  |  |
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum percentage of Free Cash Flow contributed to AICF (as percent) |  |  |  |  |  |  | 35.00% |  |  |  |  |  |  |
Net cash provided by operating activities |  |  |  |  |  |  | $ 288,400,000 |  |  |  |  |  |  |
AICF Funding | Scenario, Forecast [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payment to fund | $ 100,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition Comprised of changes in actuarial estimates received as of March 31 each year and the effect of foreign exchange movements in the asbestos related assets and liabilities which are denominated in Australian dollars. + References No definition available. + Details
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- Definition Total portion of carrying amounts as of the balance sheet date of AICF drawdown of loan facility with The State of New South Wales Australia. + References No definition available. + Details
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- Definition Maximum percentage of Free Cash Flow (as defined in the Amended and Restated Final Funding Agreement) in any given Financial year that is contributed to the Asbestos Injuries Compensation Fund in the next Financial Year. + References No definition available. + Details
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- Definition Under the terms of the Amended and Restated Final Funding Agreement (AFFA), a wholly owned Australian subsidiary (the Performing Subsidiary) has an obligation to make payments to the AICF on an annual basis. The amount of these annual payments is dependent on several factors, including the Company's free cash flow (as defined by the AFFA), actuarial estimations, actual claims paid, operating expenses of the AICF and the annual cash flow cap. + References No definition available. + Details
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