Asbestos - Additional Information (Detail) |
3 Months Ended | 12 Months Ended | 48 Months Ended | ||||||||||||
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Jul. 02, 2018
USD ($)
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Mar. 31, 2018
USD ($)
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Dec. 31, 2017
USD ($)
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Dec. 31, 2017
AUD ($)
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Mar. 31, 2017
USD ($)
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Mar. 31, 2016
USD ($)
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Mar. 31, 2018
USD ($)
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Mar. 31, 2018
AUD ($)
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Mar. 31, 2017
USD ($)
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Mar. 31, 2016
USD ($)
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Mar. 31, 2018
USD ($)
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Mar. 31, 2018
AUD ($)
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Mar. 31, 2018
AUD ($)
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Jul. 31, 2017
USD ($)
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Jul. 31, 2017
AUD ($)
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| Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items] | |||||||||||||||
| Asbestos adjustments | $ 43,600,000 | $ 56,800,000 | $ 156,400,000 | $ (40,400,000) | $ (5,500,000) | ||||||||||
| Discounted (but inflated) central estimate lower range value | $ 1,000,000,000 | 1,000,000,000 | $ 1,000,000,000 | $ 1,300,000,000 | |||||||||||
| Discounted (but inflated) central estimate high range value | 2,400,000,000 | 2,400,000,000 | 2,400,000,000 | 3,100,000,000 | |||||||||||
| Undiscounted (but inflated) central estimate lower range value | 1,300,000,000 | 1,300,000,000 | 1,300,000,000 | 1,700,000,000 | |||||||||||
| Undiscounted (but inflated) central estimate high range value | 3,200,000,000 | 3,200,000,000 | 3,200,000,000 | 4,200,000,000 | |||||||||||
| Payment to fund | 102,200,000 | 91,100,000 | $ 62,800,000 | 369,100,000 | $ 456,800,000 | ||||||||||
| Net cash provided by operating activities | 292,100,000 | $ 260,400,000 | $ 179,500,000 | 295,000,000 | |||||||||||
| Restricted short-term investments - Asbestos | $ 38,400,000 | 0 | $ 38,400,000 | 0 | $ 38,400,000 | $ 50,000,000 | $ 76,800,000 | $ 100,000,000 | |||||||
| Time deposit interest rate (as percent) | 2.32% | 2.32% | 2.32% | 2.32% | |||||||||||
| Secured standby loan facility maximum borrowing capacity | $ 245,800,000 | $ 245,800,000 | $ 245,800,000 | $ 320,000,000.0 | |||||||||||
| Maturity date of secured standby loan facility | Nov. 01, 2030 | Nov. 01, 2030 | |||||||||||||
| Loan facility, outstanding balance | $ 0 | $ 52,400,000 | $ 0 | $ 52,400,000 | $ 0 | ||||||||||
| Rate of interest of Benchmark Bonds (as percent) | 6.00% | 6.00% | |||||||||||||
| Maturity date of Benchmark Bonds | May 01, 2020 | May 01, 2020 | |||||||||||||
| AICF Funding [Member] | |||||||||||||||
| Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items] | |||||||||||||||
| Asbestos adjustments | $ 800,000 | ||||||||||||||
| Payment to fund | $ 102,200,000 | $ 135,100,000 | |||||||||||||
| Maximum percentage of Free Cash Flow contributed to AICF (as percent) | 35.00% | 35.00% | |||||||||||||
| Net cash provided by operating activities | $ 294,200,000 | ||||||||||||||
| Restricted short-term investments - Asbestos | $ 0 | ||||||||||||||
| AICF Funding [Member] | Scenario, Forecast [Member] | |||||||||||||||
| Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items] | |||||||||||||||
| Payment to fund | $ 103,000,000 | ||||||||||||||